text:
Cell nucleus
From Wikipedia, the free encyclopedia
Jump to: navigation, search
HeLa cells stained for nuclear DNA with the Blue Hoechst dye. The central and rightmost cell are in interphase, thus their entire nuclei are labeled. On the left, a cell is going through mitosis and its DNA has condensed.
Cell biology
The animal cell
Components of a typical animal cell:
Nucleolus
Nucleus
Ribosome (little dots)
Vesicle
Rough endoplasmic reticulum
Golgi apparatus (or "Golgi body")
Cytoskeleton
Smooth endoplasmic reticulum
Mitochondrion
Vacuole
Cytosol (fluid that contains organelles, comprising the cytoplasm)
Lysosome
Centrosome
Cell membrane
In cell biology, the nucleus (pl. nuclei; from Latin nucleus or nuculeus, meaning kernel or seed) is a membrane-enclosed organelle found in eukaryotic cells. Eukaryotes usually have a single nucleus, but a few cell types, such as mammalian red blood cells, have no nuclei, and a few others have many. Human skeletal muscle cells have more than one nucleus, as do eukaryotes like fungi.[1]
Cell nuclei contain most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these chromosomes are the cell's nuclear genome and are structured in such a way to promote cell function. The nucleus maintains the integrity of genes and controls the activities of the cell by regulating gene expression—the nucleus is, therefore, the control center of the cell. The main structures making up the nucleus are the nuclear envelope, a double membrane that encloses the entire organelle and isolates its contents from the cellular cytoplasm, and the nuclear matrix (which includes the nuclear lamina), a network within the nucleus that adds mechanical support, much like the cytoskeleton, which supports the cell as a whole.
Because the nuclear membrane is impermeable to large molecules, nuclear pores are required to regulate nuclear transport of molecules across the envelope. The pores cross both nuclear membranes, providing a channel through which larger molecules must be actively transported by carrier proteins while allowing free movement of small molecules and ions. Movement of large molecules such as proteins and RNA through the pores is required for both gene expression and the maintenance of chromosomes. Although the interior of the nucleus does not contain any membrane-bound sub compartments, its contents are not uniform, and a number of sub-nuclear bodies exist, made up of unique proteins, RNA molecules, and particular parts of the chromosomes. The best-known of these is the nucleolus, which is mainly involved in the assembly of ribosomes. After being produced in the nucleolus, ribosomes are exported to the cytoplasm where they translate mRNA.
Contents
[hide]
1 History
2 Structures
2.1 Nuclear envelope and pores
2.2 Nuclear lamina
2.3 Chromosomes
2.4 Nucleolus
2.5 Other subnuclear bodies
2.5.1 Cajal bodies and gems
2.5.2 RAFA and PTF domains
2.5.3 PML bodies
2.5.4 Splicing speckles
2.5.5 Paraspeckles
2.5.6 Perichromatin fibrils
3 Function
3.1 Cell compartmentalization
3.2 Gene expression
3.3 Processing of pre-mRNA
4 Dynamics and regulation
4.1 Nuclear transport
4.2 Assembly and disassembly
4.3 Disease-related dynamics
5 Nuclei per cell
5.1 Anucleated cells
5.2 Multinucleated cells
6 Evolution
7 See also
8 References
9 Further reading
10 External links
History
Oldest known depiction of cells and their nuclei by Antonie van Leeuwenhoek, 1719
Drawing of a Chironomus salivary gland cell published by Walther Flemming in 1882. The nucleus contains Polytene chromosomes.
The nucleus was the first organelle to be discovered. What is most likely the oldest preserved drawing dates back to the early microscopist Antonie van Leeuwenhoek (1632–1723). He observed a "lumen", the nucleus, in the red blood cells of salmon.[2] Unlike mammalian red blood cells, those of other vertebrates still contain nuclei.
The nucleus was also described by Franz Bauer in 1804[3] and in more detail in 1831 by Scottish botanist Robert Brown in a talk at the Linnean Society of London. Brown was studying orchids under microscope when he observed an opaque area, which he called the "areola" or "nucleus", in the cells of the flower's outer layer.[4]
He did not suggest a potential function. In 1838, Matthias Schleiden proposed that the nucleus plays a role in generating cells, thus he introduced the name "cytoblast" (cell builder). He believed that he had observed new cells assembling around "cytoblasts". Franz Meyen was a strong opponent of this view, having already described cells multiplying by division and believing that many cells would have no nuclei. The idea that cells can be generated de novo, by the "cytoblast" or otherwise, contradicted work by Robert Remak (1852) and Rudolf Virchow (1855) who decisively propagated the new paradigm that cells are generated solely by cells ("Omnis cellula e cellula"). The function of the nucleus remained unclear.[5]
Between 1877 and 1878, Oscar Hertwig published several studies on the fertilization of sea urchin eggs, showing that the nucleus of the sperm enters the oocyte and fuses with its nucleus. This was the first time it was suggested that an individual develops from a (single) nucleated cell. This was in contradiction to Ernst Haeckel's theory that the complete phylogeny of a species would be repeated during embryonic development, including generation of the first nucleated cell from a "monerula", a structureless mass of primordial mucus ("Urschleim"). Therefore, the necessity of the sperm nucleus for fertilization was discussed for quite some time. However, Hertwig confirmed his observation in other animal groups, including amphibians and molluscs. Eduard Strasburger produced the same results for plants in 1884. This paved the way to assign the nucleus an important role in heredity. In 1873, August Weismann postulated the equivalence of the maternal and paternal germ cells for heredity. The function of the nucleus as carrier of genetic information became clear only later, after mitosis was discovered and the Mendelian rules were rediscovered at the beginning of the 20th century; the chromosome theory of heredity was therefore developed.[5]
Structures
The nucleus is the largest cellular organelle in animal cells.[6] In mammalian cells, the average diameter of the nucleus is approximately 6 micrometres (µm), which occupies about 10% of the total cell volume.[7] The viscous liquid within it is called nucleoplasm (or karyolymph), and is similar in composition to the cytosol found outside the nucleus.[8] It appears as a dense, roughly spherical or irregular organelle. The composition by dry weight of the nucleus is approximately: DNA 9%, RNA 1%, Histone Protein 11%, Residual Protein 14%, Acidic Proteins 65%.
Nuclear envelope and pores
Main articles: Nuclear envelope and Nuclear pores
The eukaryotic cell nucleus. Visible in this diagram are the ribosome-studded double membranes of the nuclear envelope, the DNA (complexed as chromatin), and the nucleolus. Within the cell nucleus is a viscous liquid called nucleoplasm, similar to the cytoplasm found outside the nucleus.
A cross section of a nuclear pore on the surface of the nuclear envelope (1). Other diagram labels show (2) the outer ring, (3) spokes, (4) basket, and (5) filaments.
The nuclear envelope, otherwise known as nuclear membrane, consists of two cellular membranes, an inner and an outer membrane, arranged parallel to one another and separated by 10 to 50 nanometres (nm). The nuclear envelope completely encloses the nucleus and separates the cell's genetic material from the surrounding cytoplasm, serving as a barrier to prevent macromolecules from diffusing freely between the nucleoplasm and the cytoplasm.[9] The outer nuclear membrane is continuous with the membrane of the rough endoplasmic reticulum (RER), and is similarly studded with ribosomes.[9] The space between the membranes is called the perinuclear space and is continuous with the RER lumen.
Nuclear pores, which provide aqueous channels through the envelope, are composed of multiple proteins, collectively referred to as nucleoporins. The pores are about 125 million daltons in molecular weight and consist of around 50 (in yeast) to several hundred proteins (in vertebrates).[6] The pores are 100 nm in total diameter; however, the gap through which molecules freely diffuse is only about 9 nm wide, due to the presence of regulatory systems within the center of the pore. This size selectively allows the passage of small water-soluble molecules while preventing larger molecules, such as nucleic acids and larger proteins, from inappropriately entering or exiting the nucleus. These large molecules must be actively transported into the nucleus instead. The nucleus of a typical mammalian cell will have about 3000 to 4000 pores throughout its envelope,[10] each of which contains an eightfold-symmetric ring-shaped structure at a position where the inner and outer membranes fuse.[11] Attached to the ring is a structure called the nuclear basket that extends into the nucleoplasm, and a series of filamentous extensions that reach into the cytoplasm. Both structures serve to mediate binding to nuclear transport proteins.[6]
Most proteins, ribosomal subunits, and some DNAs are transported through the pore complexes in a process mediated by a family of transport factors known as karyopherins. Those karyopherins that mediate movement into the nucleus are also called importins, whereas those that mediate movement out of the nucleus are called exportins. Most karyopherins interact directly with their cargo, although some use adaptor proteins.[12] Steroid hormones such as cortisol and aldosterone, as well as other small lipid-soluble molecules involved in intercellular signaling, can diffuse through the cell membrane and into the cytoplasm, where they bind nuclear receptor proteins that are trafficked into the nucleus. There they serve as transcription factors when bound to their ligand; in the absence of a ligand, many such receptors function as histone deacetylases that repress gene expression.[6]
Nuclear lamina
Main article: Nuclear lamina
In animal cells, two networks of intermediate filaments provide the nucleus with mechanical support: The nuclear lamina forms an organized meshwork on the internal face of the envelope, while less organized support is provided on the cytosolic face of the envelope. Both systems provide structural support for the nuclear envelope and anchoring sites for chromosomes and nuclear pores.[7]
The nuclear lamina is composed mostly of lamin proteins. Like all proteins, lamins are synthesized in the cytoplasm and later transported to the nucleus interior, where they are assembled before being incorporated into the existing network of nuclear lamina.[13][14] Lamins found on the cytosolic face of the membrane, such as emerin and nesprin, bind to the cytoskeleton to provide structural support. Lamins are also found inside the nucleoplasm where they form another regular structure, known as the nucleoplasmic veil,[15] that is visible using fluorescence microscopy. The actual function of the veil is not clear, although it is excluded from the nucleolus and is present during interphase.[16] Lamin structures that make up the veil, such as LEM3, bind chromatin and disrupting their structure inhibits transcription of protein-coding genes.[17]
Like the components of other intermediate filaments, the lamin monomer contains an alpha-helical domain used by two monomers to coil around each other, forming a dimer structure called a coiled coil. Two of these dimer structures then join side by side, in an antiparallel arrangement, to form a tetramer called a protofilament. Eight of these protofilaments form a lateral arrangement that is twisted to form a ropelike filament. These filaments can be assembled or disassembled in a dynamic manner, meaning that changes in the length of the filament depend on the competing rates of filament addition and removal.[7]
Mutations in lamin genes leading to defects in filament assembly cause a group of rare genetic disorders known as laminopathies. The most notable laminopathy is the family of diseases known as progeria, which causes the appearance of premature aging in its sufferers. The exact mechanism by which the associated biochemical changes give rise to the aged phenotype is not well understood.[18]
Chromosomes
Main article: Chromosome
A mouse fibroblast nucleus in which DNA is stained blue. The distinct chromosome territories of chromosome 2 (red) and chromosome 9 (green) are stained with fluorescent in situ hybridization.
The cell nucleus contains the majority of the cell's genetic material in the form of multiple linear DNA molecules organized into structures called chromosomes. Each human cell contains roughly two meters of DNA. During most of the cell cycle these are organized in a DNA-protein complex known as chromatin, and during cell division the chromatin can be seen to form the well-defined chromosomes familiar from a karyotype. A small fraction of the cell's genes are located instead in the mitochondria.
There are two types of chromatin. Euchromatin is the less compact DNA form, and contains genes that are frequently expressed by the cell.[19] The other type, heterochromatin, is the more compact form, and contains DNA that is infrequently transcribed. This structure is further categorized into facultative heterochromatin, consisting of genes that are organized as heterochromatin only in certain cell types or at certain stages of development, and constitutive heterochromatin that consists of chromosome structural components such as telomeres and centromeres.[20] During interphase the chromatin organizes itself into discrete individual patches,[21] called chromosome territories.[22] Active genes, which are generally found in the euchromatic region of the chromosome, tend to be located towards the chromosome's territory boundary.[23]
Antibodies to certain types of chromatin organization, in particular, nucleosomes, have been associated with a number of autoimmune diseases, such as systemic lupus erythematosus.[24] These are known as anti-nuclear antibodies (ANA) and have also been observed in concert with multiple sclerosis as part of general immune system dysfunction.[25] As in the case of progeria, the role played by the antibodies in inducing the symptoms of autoimmune diseases is not obvious.
Nucleolus
Main article: Nucleolus
An electron micrograph of a cell nucleus, showing the darkly stained nucleolus
3D rendering of nucleus with location of nucleolus
The nucleolus is a discrete densely stained structure found in the nucleus. It is not surrounded by a membrane, and is sometimes called a suborganelle. It forms around tandem repeats of rDNA, DNA coding for ribosomal RNA (rRNA). These regions are called nucleolar organizer regions (NOR). The main roles of the nucleolus are to synthesize rRNA and assemble ribosomes. The structural cohesion of the nucleolus depends on its activity, as ribosomal assembly in the nucleolus results in the transient association of nucleolar components, facilitating further ribosomal assembly, and hence further association. This model is supported by observations that inactivation of rDNA results in intermingling of nucleolar structures.[26]
In the first step of ribosome assembly, a protein called RNA polymerase I transcribes rDNA, which forms a large pre-rRNA precursor. This is cleaved into the subunits 5.8S, 18S, and 28S rRNA.[27] The transcription, post-transcriptional processing, and assembly of rRNA occurs in the nucleolus, aided by small nucleolar RNA (snoRNA) molecules, some of which are derived from spliced introns from messenger RNAs encoding genes related to ribosomal function. The assembled ribosomal subunits are the largest structures passed through the nuclear pores.[6]
When observed under the electron microscope, the nucleolus can be seen to consist of three distinguishable regions: the innermost fibrillar centers (FCs), surrounded by the dense fibrillar component (DFC), which in turn is bordered by the granular component (GC). Transcription of the rDNA occurs either in the FC or at the FC-DFC boundary, and, therefore, when rDNA transcription in the cell is increased, more FCs are detected. Most of the cleavage and modification of rRNAs occurs in the DFC, while the latter steps involving protein assembly onto the ribosomal subunits occur in the GC.[27]
Other subnuclear bodies
Subnuclear structure sizes
Structure name
Structure diameter
Cajal bodies 0.2–2.0 µm [28]
Clastosomes 0.2-0.5 µm [29]
PIKA 5 µm [30]
PML bodies 0.2–1.0 µm [31]
Paraspeckles 0.2–1.0 µm [32]
Speckles 20–25 nm [30]
Besides the nucleolus, the nucleus contains a number of other non-membrane-delineated bodies. These include Cajal bodies, Gemini of coiled bodies, polymorphic interphase karyosomal association (PIKA), promyelocytic leukaemia (PML) bodies, paraspeckles, and splicing speckles. Although little is known about a number of these domains, they are significant in that they show that the nucleoplasm is not a uniform mixture, but rather contains organized functional subdomains.[31]
Other subnuclear structures appear as part of abnormal disease processes. For example, the presence of small intranuclear rods has been reported in some cases of nemaline myopathy. This condition typically results from mutations in actin, and the rods themselves consist of mutant actin as well as other cytoskeletal proteins.[33]
Cajal bodies and gems
A nucleus typically contains between 1 and 10 compact structures called Cajal bodies or coiled bodies (CB), whose diameter measures between 0.2 µm and 2.0 µm depending on the cell type and species.[28] When seen under an electron microscope, they resemble balls of tangled thread[30] and are dense foci of distribution for the protein coilin.[34] CBs are involved in a number of different roles relating to RNA processing, specifically small nucleolar RNA (snoRNA) and small nuclear RNA (snRNA) maturation, and histone mRNA modification.[28]
Similar to Cajal bodies are Gemini of Cajal bodies, or gems, whose name is derived from the Gemini constellation in reference to their close "twin" relationship with CBs. Gems are similar in size and shape to CBs, and in fact are virtually indistinguishable under the microscope.[34] Unlike CBs, gems do not contain small nuclear ribonucleoproteins (snRNPs), but do contain a protein called survival of motor neuron (SMN) whose function relates to snRNP biogenesis. Gems are believed to assist CBs in snRNP biogenesis,[35] though it has also been suggested from microscopy evidence that CBs and gems are different manifestations of the same structure.[34] Later ultrastructural studies have shown gems to be twins of Cajal bodies with the difference being in the coilin component; Cajal bodies are SMN positive and coilin positive, and gems are SMN positive and coilin negative.[36]
RAFA and PTF domains
RAFA domains, or polymorphic interphase karyosomal associations, were first described in microscopy studies in 1991. Their function remains unclear, though they were not thought to be associated with active DNA replication, transcription, or RNA processing.[37] They have been found to often associate with discrete domains defined by dense localization of the transcription factor PTF, which promotes transcription of small nuclear RNA (snRNA).[38]
PML bodies
Promyelocytic leukaemia bodies (PML bodies) are spherical bodies found scattered throughout the nucleoplasm, measuring around 0.1–1.0 µm. They are known by a number of other names, including nuclear domain 10 (ND10), Kremer bodies, and PML oncogenic domains. PML bodies are named after one of their major components, the promyelocytic leukemia protein (PML). They are often seen in the nucleus in association with Cajal bodies and cleavage bodies.[31] PML bodies belong to the nuclear matrix, an ill-defined super-structure of the nucleus proposed to anchor and regulate many nuclear functions, including DNA replication, transcription, or epigenetic silencing.[39] The PML protein is the key organizer of these domains that recruits an ever-growing number of proteins, whose only common known feature to date is their ability to be SUMOylated. Yet, pml-/- mice (which have their PML gene deleted) cannot assemble nuclear bodies, develop normally and live well, demonstrating that PML bodies are dispensable for most basic biological functions.[39]
Splicing speckles
Speckles are subnuclear structures that are enriched in pre-messenger RNA splicing factors and are located in the interchromatin regions of the nucleoplasm of mammalian cells. At the fluorescence-microscope level they appear as irregular, punctate structures, which vary in size and shape, and when examined by electron microscopy they are seen as clusters of interchromatin granules. Speckles are dynamic structures, and both their protein and RNA-protein components can cycle continuously between speckles and other nuclear locations, including active transcription sites. Studies on the composition, structure and behaviour of speckles have provided a model for understanding the functional compartmentalization of the nucleus and the organization of the gene-expression machinery[40] splicing snRNPs[41][42] and other splicing proteins necessary for pre-mRNA processing.[43] Because of a cell's changing requirements, the composition and location of these bodies changes according to mRNA transcription and regulation via phosphorylation of specific proteins.[44] The splicing speckles are also known as nuclear speckles (nuclear specks), splicing factor compartments (SF compartments), interchromatin granule clusters (IGCs), B snurposomes.[45] B snurposomes are found in the amphibian oocyte nuclei and in Drosophila melanogaster embryos. B snurposomes appear alone or attached to the Cajal bodies in the electron micrographs of the amphibian nuclei.[46] IGCs function as storage sites for the splicing factors.[47]
Paraspeckles
Main article: Paraspeckle
Discovered by Fox et al. in 2002, paraspeckles are irregularly shaped compartments in the nucleus' interchromatin space.[48] First documented in HeLa cells, where there are generally 10–30 per nucleus,[49] paraspeckles are now known to also exist in all human primary cells, transformed cell lines, and tissue sections.[50] Their name is derived from their distribution in the nucleus; the "para" is short for parallel and the "speckles" refers to the splicing speckles to which they are always in close proximity.[49]
Paraspeckles are dynamic structures that are altered in response to changes in cellular metabolic activity. They are transcription dependent[48] and in the absence of RNA Pol II transcription, the paraspeckle disappears and all of its associated protein components (PSP1, p54nrb, PSP2, CFI(m)68, and PSF) form a crescent shaped perinucleolar cap in the nucleolus. This phenomenon is demonstrated during the cell cycle. In the cell cycle, paraspeckles are present during interphase and during all of mitosis except for telophase. During telophase, when the two daughter nuclei are formed, there is no RNA Pol II transcription so the protein components instead form a perinucleolar cap.[50]
Perichromatin fibrils
Perichromatin fibrils are visible only under electron microscope. They are located next to the transcriptionally active chromatin and are hypothesized to be the sites of active pre-mRNA processing.[47]
Clastosome
Clastosomes are small nuclear bodies (0.2-0.5 µm) described as donut-shaped due to the peripheral capsule around these bodies.[29] This name is derived from the Greek klastos, broken and soma, body.[29] Clastosomes are not typically present in normal cells, making them hard to detect. They form under high proteolysis conditions within the nucleus and degrade once there is a decrease in activity or if cells are treated with proteasome inhibitors.[29][51] The scarcity of clastosomes in cells indicates that they are not required for proteasome function.[52] Osmotic stress has also been shown to cause the formation of clastosomes. [53] These nuclear bodies contain catalytic and regulatory sub-units of the proteasome and its substrates, indicating that clastosomes are sites for degrading proteins.[52]
The Clastosome would be an important addition to the ‘Cell Nucleus’ Wiki page because it plays a role in cell function. With further research, we may discover that this nuclear body has a more influential job in cell function than what is already known. [29]
Function
The nucleus provides a site for genetic transcription that is segregated from the location of translation in the cytoplasm, allowing levels of gene regulation that are not available to prokaryotes. The main function of the cell nucleus is to control gene expression and mediate the replication of DNA during the cell cycle.
The nucleus is an organelle found in eukaryotic cells. Inside its fully enclosed nuclear membrane, it contains the majority of the cell's genetic material. This material is organized as DNA molecules, along with a variety of proteins, to form chromosomes.
Cell compartmentalization
The nuclear envelope allows the nucleus to control its contents, and separate them from the rest of the cytoplasm where necessary. This is important for controlling processes on either side of the nuclear membrane. In most cases where a cytoplasmic process needs to be restricted, a key participant is removed to the nucleus, where it interacts with transcription factors to downregulate the production of certain enzymes in the pathway. This regulatory mechanism occurs in the case of glycolysis, a cellular pathway for breaking down glucose to produce energy. Hexokinase is an enzyme responsible for the first the step of glycolysis, forming glucose-6-phosphate from glucose. At high concentrations of fructose-6-phosphate, a molecule made later from glucose-6-phosphate, a regulator protein removes hexokinase to the nucleus,[54] where it forms a transcriptional repressor complex with nuclear proteins to reduce the expression of genes involved in glycolysis.[55]
In order to control which genes are being transcribed, the cell separates some transcription factor proteins responsible for regulating gene expression from physical access to the DNA until they are activated by other signaling pathways. This prevents even low levels of inappropriate gene expression. For example, in the case of NF-κB-controlled genes, which are involved in most inflammatory responses, transcription is induced in response to a signal pathway such as that initiated by the signaling molecule TNF-α, binds to a cell membrane receptor, resulting in the recruitment of signalling proteins, and eventually activating the transcription factor NF-κB. A nuclear localisation signal on the NF-κB protein allows it to be transported through the nuclear pore and into the nucleus, where it stimulates the transcription of the target genes.[7]
The compartmentalization allows the cell to prevent translation of unspliced mRNA.[56] Eukaryotic mRNA contains introns that must be removed before being translated to produce functional proteins. The splicing is done inside the nucleus before the mRNA can be accessed by ribosomes for translation. Without the nucleus, ribosomes would translate newly transcribed (unprocessed) mRNA, resulting in malformed and nonfunctional proteins.
Gene expression
Main article: Gene expression
A micrograph of ongoing gene transcription of ribosomal RNA illustrating the growing primary transcripts. "Begin" indicates the 5' end of the DNA, where new RNA synthesis begins; "end" indicates the 3' end, where the primary transcripts are almost complete.
Gene expression first involves transcription, in which DNA is used as a template to produce RNA. In the case of genes encoding proteins, that RNA produced from this process is messenger RNA (mRNA), which then needs to be translated by ribosomes to form a protein. As ribosomes are located outside the nucleus, mRNA produced needs to be exported.[57]
Since the nucleus is the site of transcription, it also contains a variety of proteins that either directly mediate transcription or are involved in regulating the process. These proteins include helicases, which unwind the double-stranded DNA molecule to facilitate access to it, RNA polymerases, which bind to the DNA promoter to synthesize the growing RNA molecule, topoisomerases, which change the amount of supercoiling in DNA, helping it wind and unwind, as well as a large variety of transcription factors that regulate expression.[58]
Processing of pre-mRNA
Main article: Post-transcriptional modification
Newly synthesized mRNA molecules are known as primary transcripts or pre-mRNA. They must undergo post-transcriptional modification in the nucleus before being exported to the cytoplasm; mRNA that appears in the cytoplasm without these modifications is degraded rather than used for protein translation. The three main modifications are 5' capping, 3' polyadenylation, and RNA splicing. While in the nucleus, pre-mRNA is associated with a variety of proteins in complexes known as heterogeneous ribonucleoprotein particles (hnRNPs). Addition of the 5' cap occurs co-transcriptionally and is the first step in post-transcriptional modification. The 3' poly-adenine tail is only added after transcription is complete.
RNA splicing, carried out by a complex called the spliceosome, is the process by which introns, or regions of DNA that do not code for protein, are removed from the pre-mRNA and the remaining exons connected to re-form a single continuous molecule. This process normally occurs after 5' capping and 3' polyadenylation but can begin before synthesis is complete in transcripts with many exons.[6] Many pre-mRNAs, including those encoding antibodies, can be spliced in multiple ways to produce different mature mRNAs that encode different protein sequences. This process is known as alternative splicing, and allows production of a large variety of proteins from a limited amount of DNA.
Dynamics and regulation
Nuclear transport
Main article: Nuclear transport
Macromolecules, such as RNA and proteins, are actively transported across the nuclear membrane in a process called the Ran-GTP nuclear transport cycle.
The entry and exit of large molecules from the nucleus is tightly controlled by the nuclear pore complexes. Although small molecules can enter the nucleus without regulation,[59] macromolecules such as RNA and proteins require association karyopherins called importins to enter the nucleus and exportins to exit. "Cargo" proteins that must be translocated from the cytoplasm to the nucleus contain short amino acid sequences known as nuclear localization signals, which are bound by importins, while those transported from the nucleus to the cytoplasm carry nuclear export signals bound by exportins. The ability of importins and exportins to transport their cargo is regulated by GTPases, enzymes that hydrolyze the molecule guanosine triphosphate to release energy. The key GTPase in nuclear transport is Ran, which can bind either GTP or GDP (guanosine diphosphate), depending on whether it is located in the nucleus or the cytoplasm. Whereas importins depend on RanGTP to dissociate from their cargo, exportins require RanGTP in order to bind to their cargo.[12]
Nuclear import depends on the importin binding its cargo in the cytoplasm and carrying it through the nuclear pore into the nucleus. Inside the nucleus, RanGTP acts to separate the cargo from the importin, allowing the importin to exit the nucleus and be reused. Nuclear export is similar, as the exportin binds the cargo inside the nucleus in a process facilitated by RanGTP, exits through the nuclear pore, and separates from its cargo in the cytoplasm.
Specialized export proteins exist for translocation of mature mRNA and tRNA to the cytoplasm after post-transcriptional modification is complete. This quality-control mechanism is important due to these molecules' central role in protein translation. Mis-expression of a protein due to incomplete excision of exons or mis-incorporation of amino acids could have negative consequences for the cell; thus, incompletely modified RNA that reaches the cytoplasm is degraded rather than used in translation.[6]
Assembly and disassembly
An image of a newt lung cell stained with fluorescent dyes during metaphase. The mitotic spindle can be seen, stained green, attached to the two sets of chromosomes, stained light blue. All chromosomes but one are already at the metaphase plate.
During its lifetime, a nucleus may be broken down or destroyed, either in the process of cell division or as a consequence of apoptosis (the process of programmed cell death). During these events, the structural components of the nucleus — the envelope and lamina — can be systematically degraded. In most cells, the disassembly of the nuclear envelope marks the end of the prophase of mitosis. However, this disassembly of the nucleus is not a universal feature of mitosis and does not occur in all cells. Some unicellular eukaryotes (e.g., yeasts) undergo so-called closed mitosis, in which the nuclear envelope remains intact. In closed mitosis, the daughter chromosomes migrate to opposite poles of the nucleus, which then divides in two. The cells of higher eukaryotes, however, usually undergo open mitosis, which is characterized by breakdown of the nuclear envelope. The daughter chromosomes then migrate to opposite poles of the mitotic spindle, and new nuclei reassemble around them.
At a certain point during the cell cycle in open mitosis, the cell divides to form two cells. In order for this process to be possible, each of the new daughter cells must have a full set of genes, a process requiring replication of the chromosomes as well as segregation of the separate sets. This occurs by the replicated chromosomes, the sister chromatids, attaching to microtubules, which in turn are attached to different centrosomes. The sister chromatids can then be pulled to separate locations in the cell. In many cells, the centrosome is located in the cytoplasm, outside the nucleus; the microtubules would be unable to attach to the chromatids in the presence of the nuclear envelope.[60] Therefore, the early stages in the cell cycle, beginning in prophase and until around prometaphase, the nuclear membrane is dismantled.[15] Likewise, during the same period, the nuclear lamina is also disassembled, a process regulated by phosphorylation of the lamins by protein kinases such as the CDC2 protein kinase.[61] Towards the end of the cell cycle, the nuclear membrane is reformed, and around the same time, the nuclear lamina are reassembled by dephosphorylating the lamins.[61]
However, in dinoflagellates, the nuclear envelope remains intact, the centrosomes are located in the cytoplasm, and the microtubules come in contact with chromosomes, whose centromeric regions are incorporated into the nuclear envelope (the so-called closed mitosis with extranuclear spindle). In many other protists (e.g., ciliates, sporozoans) and fungi, the centrosomes are intranuclear, and their nuclear envelope also does not disassemble during cell division.
Apoptosis is a controlled process in which the cell's structural components are destroyed, resulting in death of the cell. Changes associated with apoptosis directly affect the nucleus and its contents, for example, in the condensation of chromatin and the disintegration of the nuclear envelope and lamina. The destruction of the lamin networks is controlled by specialized apoptotic proteases called caspases, which cleave the lamin proteins and, thus, degrade the nucleus' structural integrity. Lamin cleavage is sometimes used as a laboratory indicator of caspase activity in assays for early apoptotic activity.[15] Cells that express mutant caspase-resistant lamins are deficient in nuclear changes related to apoptosis, suggesting that lamins play a role in initiating the events that lead to apoptotic degradation of the nucleus.[15] Inhibition of lamin assembly itself is an inducer of apoptosis.[62]
The nuclear envelope acts as a barrier that prevents both DNA and RNA viruses from entering the nucleus. Some viruses require access to proteins inside the nucleus in order to replicate and/or assemble. DNA viruses, such as herpesvirus replicate and assemble in the cell nucleus, and exit by budding through the inner nuclear membrane. This process is accompanied by disassembly of the lamina on the nuclear face of the inner membrane.[15]
Disease-related dynamics
Initially, it has been suspected that immunoglobulins in general and autoantibodies in particular do not enter the nucleus. Now there is a body of evidence that under pathological conditions (e.g. lupus erythematosus) IgG can enter the nucleus.[63]
Nuclei per cell
Most eukaryotic cell types usually have a single nucleus, but some have no nuclei, while others have several. This can result from normal development, as in the maturation of mammalian red blood cells, or from faulty cell division.
Anucleated cells
Human red blood cells, like those of other mammals, lack nuclei. This occurs as a normal part of the cells' development.
An anucleated cell contains no nucleus and is, therefore, incapable of dividing to produce daughter cells. The best-known anucleated cell is the mammalian red blood cell, or erythrocyte, which also lacks other organelles such as mitochondria, and serves primarily as a transport vessel to ferry oxygen from the lungs to the body's tissues. Erythrocytes mature through erythropoiesis in the bone marrow, where they lose their nuclei, organelles, and ribosomes. The nucleus is expelled during the process of differentiation from an erythroblast to a reticulocyte, which is the immediate precursor of the mature erythrocyte.[64] The presence of mutagens may induce the release of some immature "micronucleated" erythrocytes into the bloodstream.[65][66] Anucleated cells can also arise from flawed cell division in which one daughter lacks a nucleus and the other has two nuclei.
In flowering plants, this condition occurs in sieve tube elements.
Multinucleated cells
Multinucleated cells contain multiple nuclei. Most acantharean species of protozoa[67] and some fungi in mycorrhizae[68] have naturally multinucleated cells. Other examples include the intestinal parasites in the genus Giardia, which have two nuclei per cell.[69] In humans, skeletal muscle cells, called myocytes and syncytium, become multinucleated during development; the resulting arrangement of nuclei near the periphery of the cells allows maximal intracellular space for myofibrils.[6] Multinucleated and binucleated cells can also be abnormal in humans; for example, cells arising from the fusion of monocytes and macrophages, known as giant multinucleated cells, sometimes accompany inflammation[70] and are also implicated in tumor formation.[71]
A number of dinoflagellates are known to have two nuclei.[72] Unlike other multinucleated cells these nuclei contain two distinct lineages of DNA: one from the dinoflagellate and the other from a symbiotic diatom. The mitochondria and the plastids of the diatom somehow remain functional.
Evolution
As the major defining characteristic of the eukaryotic cell, the nucleus' evolutionary origin has been the subject of much speculation. Four major hypotheses have been proposed to explain the existence of the nucleus, although none have yet earned widespread support.[73]
The first model known as the "syntrophic model" proposes that a symbiotic relationship between the archaea and bacteria created the nucleus-containing eukaryotic cell. (Organisms of the Archaea and Bacteria domain have no cell nucleus.[74]) It is hypothesized that the symbiosis originated when ancient archaea, similar to modern methanogenic archaea, invaded and lived within bacteria similar to modern myxobacteria, eventually forming the early nucleus. This theory is analogous to the accepted theory for the origin of eukaryotic mitochondria and chloroplasts, which are thought to have developed from a similar endosymbiotic relationship between proto-eukaryotes and aerobic bacteria.[75] The archaeal origin of the nucleus is supported by observations that archaea and eukarya have similar genes for certain proteins, including histones. Observations that myxobacteria are motile, can form multicellular complexes, and possess kinases and G proteins similar to eukarya, support a bacterial origin for the eukaryotic cell.[76]
A second model proposes that proto-eukaryotic cells evolved from bacteria without an endosymbiotic stage. This model is based on the existence of modern planctomycetes bacteria that possess a nuclear structure with primitive pores and other compartmentalized membrane structures.[77] A similar proposal states that a eukaryote-like cell, the chronocyte, evolved first and phagocytosed archaea and bacteria to generate the nucleus and the eukaryotic cell.[78]
The most controversial model, known as viral eukaryogenesis, posits that the membrane-bound nucleus, along with other eukaryotic features, originated from the infection of a prokaryote by a virus. The suggestion is based on similarities between eukaryotes and viruses such as linear DNA strands, mRNA capping, and tight binding to proteins (analogizing histones to viral envelopes). One version of the proposal suggests that the nucleus evolved in concert with phagocytosis to form an early cellular "predator".[79] Another variant proposes that eukaryotes originated from early archaea infected by poxviruses, on the basis of observed similarity between the DNA polymerases in modern poxviruses and eukaryotes.[80][81] It has been suggested that the unresolved question of the evolution of sex could be related to the viral eukaryogenesis hypothesis.[82]
A more recent proposal, the exomembrane hypothesis, suggests that the nucleus instead originated from a single ancestral cell that evolved a second exterior cell membrane; the interior membrane enclosing the original cell then became the nuclear membrane and evolved increasingly elaborate pore structures for passage of internally synthesized cellular components such as ribosomal subunits.[83]
See also
Nucleus (neuroanatomy)
References
Jump up ^ "Cell Nucleus". biologydictionary.net. Retrieved 31 July 2017.
Jump up ^ Leeuwenhoek, A. van: Opera Omnia, seu Arcana Naturae ope exactissimorum Microscopiorum detecta, experimentis variis comprobata, Epistolis ad varios illustres viros. J. Arnold et Delphis, A. Beman, Lugdinum Batavorum 1719–1730. Cited after: Dieter Gerlach, Geschichte der Mikroskopie. Verlag Harri Deutsch, Frankfurt am Main, Germany, 2009. ISBN 978-3-8171-1781-9.
Jump up ^ Harris, H (1999). The Birth of the Cell. New Haven: Yale University Press. ISBN 0-300-07384-4.
Jump up ^ Brown, Robert (1866). "On the Organs and Mode of Fecundation of Orchidex and Asclepiadea". Miscellaneous Botanical Works I: 511–514.
^ Jump up to: a b Cremer, Thomas (1985). Von der Zellenlehre zur Chromosomentheorie. Berlin, Heidelberg, New York, Tokyo: Springer Verlag. ISBN 3-540-13987-7. Online Version here
^ Jump up to: a b c d e f g h Lodish, H; Berk A; Matsudaira P; Kaiser CA; Krieger M; Scott MP; Zipursky SL; Darnell J. (2004). Molecular Cell Biology (5th ed.). New York: WH Freeman. ISBN 0-7167-2672-6.
^ Jump up to: a b c d Bruce Alberts; Alexander Johnson; Julian Lewis; Martin Raff; Keith Roberts; Peter Walter, eds. (2002). Molecular Biology of the Cell, Chapter 4, pages 191–234 (4th ed.). Garland Science.
Jump up ^ Clegg JS (February 1984). "Properties and metabolism of the aqueous cytoplasm and its boundaries". Am. J. Physiol. 246 (2 Pt 2): R133–51. PMID 6364846.
^ Jump up to: a b Paine P, Moore L, Horowitz S (1975). "Nuclear envelope permeability". Nature. 254 (5496): 109–114. doi:10.1038/254109a0. PMID 1117994.
Jump up ^ Rodney Rhoades; Richard Pflanzer, eds. (1996). "Ch3". Human Physiology (3rd ed.). Saunders College Publishing.
Jump up ^ Shulga N, Mosammaparast N, Wozniak R, Goldfarb D (2000). "Yeast nucleoporins involved in passive nuclear envelope permeability". J Cell Biol. 149 (5): 1027–1038. doi:10.1083/jcb.149.5.1027. PMC 2174828  . PMID 10831607.
^ Jump up to: a b Pemberton L, Paschal B (2005). "Mechanisms of receptor-mediated nuclear import and nuclear export". Traffic. 6 (3): 187–198. doi:10.1111/j.1600-0854.2005.00270.x. PMID 15702987.
Jump up ^ Stuurman N, Heins S, Aebi U (1998). "Nuclear lamins: their structure, assembly, and interactions". J Struct Biol. 122 (1–2): 42–66. doi:10.1006/jsbi.1998.3987. PMID 9724605.
Jump up ^ Goldman A, Moir R, Montag-Lowy M, Stewart M, Goldman R (1992). "Pathway of incorporation of microinjected lamin A into the nuclear envelope". J Cell Biol. 119 (4): 725–735. doi:10.1083/jcb.119.4.725. PMC 2289687  . PMID 1429833.
^ Jump up to: a b c d e Goldman R, Gruenbaum Y, Moir R, Shumaker D, Spann T (2002). "Nuclear lamins: building blocks of nuclear architecture". Genes Dev. 16 (5): 533–547. doi:10.1101/gad.960502. PMID 11877373.
Jump up ^ Moir RD, Yoona M, Khuona S, Goldman RD (2000). "Nuclear Lamins A and B1: Different Pathways of Assembly during Nuclear Envelope Formation in Living Cells". Journal of Cell Biology. 151 (6): 1155–1168. doi:10.1083/jcb.151.6.1155. PMC 2190592  . PMID 11121432.
Jump up ^ Spann TP, Goldman AE, Wang C, Huang S, Goldman RD. (2002). "Alteration of nuclear lamin organization inhibits RNA polymerase II–dependent transcription". Journal of Cell Biology. 156 (4): 603–608. doi:10.1083/jcb.200112047. PMC 2174089  . PMID 11854306. CS1 maint: Uses authors parameter (link)
Jump up ^ Mounkes LC, Stewart CL (2004). "Aging and nuclear organization: lamins and progeria". Current Opinion in Cell Biology. 16 (3): 322–327. doi:10.1016/j.ceb.2004.03.009. PMID 15145358.
Jump up ^ Ehrenhofer-Murray A (2004). "Chromatin dynamics at DNA replication, transcription and repair". Eur J Biochem. 271 (12): 2335–2349. doi:10.1111/j.1432-1033.2004.04162.x. PMID 15182349.
Jump up ^ Grigoryev S, Bulynko Y, Popova E (2006). "The end adjusts the means: heterochromatin remodelling during terminal cell differentiation". Chromosome Res. 14 (1): 53–69. doi:10.1007/s10577-005-1021-6. PMID 16506096.
Jump up ^ Schardin, Margit; Cremer, T; Hager, HD; Lang, M (December 1985). "Specific staining of human chromosomes in Chinese hamster x man hybrid cell lines demonstrates interphase chromosome territories". Human Genetics. Springer Berlin / Heidelberg. 71 (4): 281–287. doi:10.1007/BF00388452. PMID 2416668.
Jump up ^ Lamond, Angus I.; William C. Earnshaw (1998-04-24). "Structure and Function in the Nucleus". Science. 280 (5363): 547–553. doi:10.1126/science.280.5363.547. PMID 9554838.
Jump up ^ Kurz, A; Lampel, S; Nickolenko, JE; Bradl, J; Benner, A; Zirbel, RM; Cremer, T; Lichter, P (1996). "Active and inactive genes localize preferentially in the periphery of chromosome territories". The Journal of Cell Biology. The Rockefeller University Press. 135 (5): 1195–1205. doi:10.1083/jcb.135.5.1195. PMC 2121085  . PMID 8947544. Archived from the original on 2007-09-29.
Jump up ^ NF Rothfield; BD Stollar (1967). "The Relation of Immunoglobulin Class, Pattern of Antinuclear Antibody, and Complement-Fixing Antibodies to DNA in Sera from Patients with Systemic Lupus Erythematosus". J Clin Invest. 46 (11): 1785–1794. doi:10.1172/JCI105669. PMC 292929  . PMID 4168731.
Jump up ^ S Barned; AD Goodman; DH Mattson (1995). "Frequency of anti-nuclear antibodies in multiple sclerosis". Neurology. 45 (2): 384–385. doi:10.1212/WNL.45.2.384. PMID 7854544.
Jump up ^ Hernandez-Verdun, Daniele (2006). "Nucleolus: from structure to dynamics". Histochem. Cell. Biol. 125 (1–2): 127–137. doi:10.1007/s00418-005-0046-4. PMID 16328431.
^ Jump up to: a b Lamond, Angus I.; Judith E. Sleeman (October 2003). "Nuclear substructure and dynamics". Current Biology. 13 (21): R825–828. doi:10.1016/j.cub.2003.10.012. PMID 14588256.
^ Jump up to: a b c Cioce M, Lamond A (2005). "Cajal bodies: a long history of discovery". Annu Rev Cell Dev Biol. 21: 105–131. doi:10.1146/annurev.cellbio.20.010403.103738. PMID 16212489.
^ Jump up to: a b c d e Lafarga, Miguel (2002-08-01). ""Clastosome: A Subtype of Nuclear Body Enriched in 19S and 20S Proteasomes, Ubiquitin, and Protein Substrates of Proteasome"". Molecular Biology of the Cell. 13: 2771–2782.
^ Jump up to: a b c Pollard, Thomas D.; William C. Earnshaw (2004). Cell Biology. Philadelphia: Saunders. ISBN 0-7216-3360-9.
^ Jump up to: a b c Dundr, Miroslav; Tom Misteli (2001). "Functional architecture in the cell nucleus". Biochem. J. 356 (Pt 2): 297–310. doi:10.1042/0264-6021:3560297. PMC 1221839  . PMID 11368755.
Jump up ^ Fox, Archa (2007-03-07). "Paraspeckle Size" (Interview). Interview with R. Sundby. E-mail Correspondence. [unreliable source?]
Jump up ^ Goebel, H.H.; I Warlow (January 1997). "Nemaline myopathy with intranuclear rods—intranuclear rod myopathy". Neuromuscular Disorders. 7 (1): 13–19. doi:10.1016/S0960-8966(96)00404-X. PMID 9132135.
^ Jump up to: a b c Matera AG, Frey MA (1998). "Coiled Bodies and Gems: Janus or Gemini?". American Journal of Human Genetics. 63 (2): 317–321. doi:10.1086/301992. PMC 1377332  . PMID 9683623.
Jump up ^ Matera, A. Gregory (1998). "Of Coiled Bodies, Gems, and Salmon". Journal of Cellular Biochemistry. 70 (2): 181–192. doi:10.1002/(sici)1097-4644(19980801)70:2<181::aid-jcb4>3.0.co;2-k. PMID 9671224.
Jump up ^ Navascues, J; Berciano, MT; Tucker, KE; Lafarga, M; Matera, AG (June 2004). "Targeting SMN to Cajal bodies and nuclear gems during neuritogenesis". Chromosoma. 112 (8): 398–409. doi:10.1007/s00412-004-0285-5. PMC 1592132  . PMID 15164213.
Jump up ^ Saunders WS, Cooke CA, Earnshaw WC (1991). "Compartmentalization within the nucleus: discovery of a novel subnuclear region". Journal of Cellular Biology. 115 (4): 919–931. doi:10.1083/jcb.115.4.919. PMC 2289954  . PMID 1955462.
Jump up ^ Pombo A, Cuello P, Schul W, Yoon J, Roeder R, Cook P, Murphy S (1998). "Regional and temporal specialization in the nucleus: a transcriptionally active nuclear domain rich in PTF, Oct1 and PIKA antigens associates with specific chromosomes early in the cell cycle". The EMBO Journal. 17 (6): 1768–1778. doi:10.1093/emboj/17.6.1768. PMC 1170524  . PMID 9501098.
^ Jump up to: a b Lallemand-Breitenbach, V.; De The, H. (2010). "PML Nuclear Bodies". Cold Spring Harbor Perspectives in Biology. 2 (5): a000661. doi:10.1101/cshperspect.a000661. PMC 2857171  . PMID 20452955.
Jump up ^ Lamond AI, Spector DL (August 2003). "Nuclear speckles: a model for nuclear organelles". Nature Reviews Molecular Cell Biology. 4 (8): 605–12. doi:10.1038/nrm1172. PMID 12923522.
Jump up ^ Tripathi K, Parnaik VK (September 2008). "Differential dynamics of splicing factor SC35 during the cell cycle" (PDF). J. Biosci. 33 (3): 345–54. doi:10.1007/s12038-008-0054-3. PMID 19005234. Archived (PDF) from the original on 2011-11-15.
Jump up ^ Tripathi, K.; Parnaik, V. K. (2008). "Differential dynamics of splicing factor SC35 during the cell cycle". Journal of biosciences. 33 (3): 345–354. doi:10.1007/s12038-008-0054-3. PMID 19005234.
Jump up ^ Lamond AI, Spector DL (August 2003). "Nuclear speckles: a model for nuclear organelles". Nature Reviews Molecular Cell Biology. 4 (8): 605–12. doi:10.1038/nrm1172. PMID 12923522.
Jump up ^ Handwerger, Korie E.; Joseph G. Gall (January 2006). "Subnuclear organelles: new insights into form and function". Trends in Cell Biology. 16 (1): 19–26. doi:10.1016/j.tcb.2005.11.005. PMID 16325406.
Jump up ^ "Cellular component Nucleus speckle". UniProt: UniProtKB. Retrieved 2013-08-30.
Jump up ^ Gall, Joseph G.; Bellini, Michel; Wu, Zheng'an; Murphy, Christine (December 1999). "Assembly of the Nuclear Transcription and Processing Machinery: Cajal Bodies (Coiled Bodies) and Transcriptosomes". Molecular Biology of the Cell. 10 (12): 4385–4402. doi:10.1091/mbc.10.12.4385. ISSN 1059-1524. PMC 25765  . PMID 10588665.
^ Jump up to: a b Matera, A. Gregory; Rebecca M. Terns; Michael P. Terns (March 2007). "Non-coding RNAs: lessons from the small nuclear and small nucleolar RNAs". Nature Reviews Molecular Cell Biology. 8 (3): 209–220. doi:10.1038/nrm2124. ISSN 1471-0072. PMID 17318225. Archived from the original on 2011-09-26. Retrieved 2013-08-09.
^ Jump up to: a b Fox, Archa; Lam, YW; Leung, AK; Lyon, CE; Andersen, J; Mann, M; Lamond, AI (2002). "Paraspeckles:A Novel Nuclear Domain". Current Biology. 12 (1): 13–25. doi:10.1016/S0960-9822(01)00632-7. PMID 11790299. [permanent dead link]
^ Jump up to: a b Fox, Archa; Wendy Bickmore (2004). "Nuclear Compartments: Paraspeckles". Nuclear Protein Database. Archived from the original on 2008-09-10. Retrieved 2007-03-06.
^ Jump up to: a b Fox, A.; et al. (2005). "P54nrb Forms a Heterodimer with PSP1 That Localizes to Paraspeckles in an RNA-dependent Manner". Molecular Biology of the Cell. 16 (11): 5304–5315. doi:10.1091/mbc.E05-06-0587. PMC 1266428  . PMID 16148043.
Jump up ^ Kong, Xiao-Ni; Yan, He-Xin; Chen, Lei; Dong, Li-Wei; Yang, Wen; Liu, Qiong; Yu, Le-Xing; Huang, Dan-Dan; Liu, Shu-Qin (2007-10-29). "LPS-induced down-regulation of signal regulatory protein α contributes to innate immune activation in macrophages". The Journal of Experimental Medicine. 204 (11): 2719–2731. doi:10.1084/jem.20062611. ISSN 0022-1007. PMC 2118489  . PMID 17954568.
^ Jump up to: a b Carmo-Fonseca, Maria; Berciano, Maria T.; Lafarga, Miguel (September 2010). "Orphan Nuclear Bodies". Cold Spring Harbor Perspectives in Biology. 2 (9). doi:10.1101/cshperspect.a000703. ISSN 1943-0264. PMC 2926751  . PMID 20610547.
Jump up ^ Sampuda, Katherine M.; Riley, Mason; Boyd, Lynn (2017-04-19). "Stress induced nuclear granules form in response to accumulation of misfolded proteins in Caenorhabditis elegans". BMC Cell Biology. 18: 18. doi:10.1186/s12860-017-0136-x. ISSN 1471-2121.
Jump up ^ Lehninger, Albert L.; Nelson, David L.; Cox, Michael M. (2000). Lehninger principles of biochemistry (3rd ed.). New York: Worth Publishers. ISBN 1-57259-931-6.
Jump up ^ Moreno F, Ahuatzi D, Riera A, Palomino CA, Herrero P (2005). "Glucose sensing through the Hxk2-dependent signalling pathway". Biochem Soc Trans. 33 (1): 265–268. doi:10.1042/BST0330265. PMID 15667322.
Jump up ^ Görlich, Dirk; Ulrike Kutay (1999). "Transport between the cell nucleus and the cytoplasm". Annu. Rev. Cell Dev. Biol. 15 (1): 607–660. doi:10.1146/annurev.cellbio.15.1.607. PMID 10611974.
Jump up ^ Nierhaus, Knud H.; Daniel N. Wilson (2004). Protein Synthesis and Ribosome Structure: Translating the Genome. Wiley-VCH. ISBN 3-527-30638-2.
Jump up ^ Nicolini, Claudio A. (1997). Genome Structure and Function: From Chromosomes Characterization to Genes Technology. Springer. ISBN 0-7923-4565-7.
Jump up ^ Watson, JD; Baker TA; Bell SP; Gann A; Levine M; Losick R. (2004). "Ch9–10". Molecular Biology of the Gene (5th ed.). Peason Benjamin Cummings; CSHL Press. ISBN 0-8053-9603-9.
Jump up ^ Lippincott-Schwartz, Jennifer (2002-03-07). "Cell biology: Ripping up the nuclear envelope". Nature. 416 (6876): 31–32. doi:10.1038/416031a. PMID 11882878.
^ Jump up to: a b Boulikas T (1995). "Phosphorylation of transcription factors and control of the cell cycle". Crit Rev Eukaryot Gene Expr. 5 (1): 1–77. PMID 7549180.
Jump up ^ Steen R, Collas P (2001). "Mistargeting of B-type lamins at the end of mitosis: implications on cell survival and regulation of lamins A/C expression". J Cell Biol. 153 (3): 621–626. doi:10.1083/jcb.153.3.621. PMC 2190567  . PMID 11331311.
Jump up ^ Böhm I. IgG deposits can be detected in cell nuclei of patients with both lupus erythematosus and malignancy. Clin Rheumatol 2007;26(11) 1877-1882
Jump up ^ Skutelsky, E.; Danon D. (June 1970). "Comparative study of nuclear expulsion from the late erythroblast and cytokinesis". J Cell Biol. 60 (60(3)): 625–635. doi:10.1016/0014-4827(70)90536-7. PMID 5422968.
Jump up ^ Torous, DK; Dertinger SD; Hall NE; Tometsko CR. (2000). "Enumeration of micronucleated reticulocytes in rat peripheral blood: a flow cytometric study". Mutat Res. 465 (465(1–2)): 91–99. doi:10.1016/S1383-5718(99)00216-8. PMID 10708974.
Jump up ^ Hutter, KJ; Stohr M. (1982). "Rapid detection of mutagen induced micronucleated erythrocytes by flow cytometry". Histochemistry. 75 (3): 353–362. doi:10.1007/bf00496738. PMID 7141888.
Jump up ^ Zettler, LA; Sogin ML; Caron DA (1997). "Phylogenetic relationships between the Acantharea and the Polycystinea: A molecular perspective on Haeckel's Radiolaria". Proc Natl Acad Sci USA. 94 (21): 11411–11416. doi:10.1073/pnas.94.21.11411. PMC 23483  . PMID 9326623.
Jump up ^ Horton, TR (2006). "The number of nuclei in basidiospores of 63 species of ectomycorrhizal Homobasidiomycetes". Mycologia. 98 (2): 233–238. doi:10.3852/mycologia.98.2.233. PMID 16894968.
Jump up ^ Adam RD (December 1991). "The biology of Giardia spp". Microbiol. Rev. 55 (4): 706–32. PMC 372844  . PMID 1779932.
Jump up ^ McInnes, A; Rennick DM (1988). "Interleukin 4 induces cultured monocytes/macrophages to form giant multinucleated cells". J Exp Med. 167 (2): 598–611. doi:10.1084/jem.167.2.598. PMC 2188835  . PMID 3258008.
Jump up ^ Goldring, SR; Roelke MS; Petrison KK; Bhan AK (1987). "Human giant cell tumors of bone identification and characterization of cell types". J Clin Invest. 79 (2): 483–491. doi:10.1172/JCI112838. PMC 424109  . PMID 3027126.
Jump up ^ Imanian, B; Pombert, JF; Dorrell, RG; Burki, F; Keeling, PJ (2012). "Tertiary endosymbiosis in two dinotoms has generated little change in the mitochondrial genomes of their dinoflagellate hosts and diatom endosymbionts". PLOS ONE. 7 (8): e43763. doi:10.1371/journal.pone.0043763. PMC 3423374  . PMID 22916303.
Jump up ^ Pennisi E. (2004). "Evolutionary biology. The birth of the nucleus". Science. 305 (5685): 766–768. doi:10.1126/science.305.5685.766. PMID 15297641.
Jump up ^ C.Michael Hogan. 2010. Archaea. eds. E.Monosson & C.Cleveland, Encyclopedia of Earth. National Council for Science and the Environment, Washington DC. Archived 2011-05-11 at the Wayback Machine.
Jump up ^ Margulis, Lynn (1981). Symbiosis in Cell Evolution. San Francisco: W. H. Freeman and Company. pp. 206–227. ISBN 0-7167-1256-3.
Jump up ^ Lopez-Garcia P, Moreira D (2006). "Selective forces for the origin of the eukaryotic nucleus". BioEssays. 28 (5): 525–533. doi:10.1002/bies.20413. PMID 16615090.
Jump up ^ Fuerst JA. (2005). "Intracellular compartmentation in planctomycetes". Annu Rev Microbiol. 59: 299–328. doi:10.1146/annurev.micro.59.030804.121258. PMID 15910279.
Jump up ^ Hartman H, Fedorov A (2002). "The origin of the eukaryotic cell: a genomic investigation". Proc Natl Acad Sci U S A. 99 (3): 1420–1425. doi:10.1073/pnas.032658599. PMC 122206  . PMID 11805300.
Jump up ^ Bell PJ (September 2001). "Viral eukaryogenesis: was the ancestor of the nucleus a complex DNA virus?". J. Mol. Evol. 53 (3): 251–6. doi:10.1007/s002390010215. PMID 11523012.
Jump up ^ Takemura M (2001). "Poxviruses and the origin of the eukaryotic nucleus". J Mol Evol. 52 (5): 419–425. doi:10.1007/s002390010171. PMID 11443345.
Jump up ^ Villarreal L, DeFilippis V (2000). "A hypothesis for DNA viruses as the origin of eukaryotic replication proteins". J Virol. 74 (15): 7079–7084. doi:10.1128/JVI.74.15.7079-7084.2000. PMC 112226  . PMID 10888648.
Jump up ^ Bell PJ (November 2006). "Sex and the eukaryotic cell cycle is consistent with a viral ancestry for the eukaryotic nucleus". J. Theor. Biol. 243 (1): 54–63. doi:10.1016/j.jtbi.2006.05.015. PMID 16846615.
Jump up ^ de Roos AD (2006). "The origin of the eukaryotic cell based on conservation of existing interfaces". Artif Life. 12 (4): 513–523. doi:10.1162/artl.2006.12.4.513. PMID 16953783.
Further reading
Library resources about
Cell nucleus
Online books
Resources in your library
Resources in other libraries
Goldman, Robert D.; Gruenbaum, Y; Moir, RD; Shumaker, DK; Spann, TP (2002). "Nuclear lamins: building blocks of nuclear architecture". Genes Dev. 16 (5): 533–547. doi:10.1101/gad.960502. PMID 11877373.
A review article about nuclear lamins, explaining their structure and various roles
Görlich, Dirk; Kutay, U (1999). "Transport between the cell nucleus and the cytoplasm". Annu. Rev. Cell Dev. Biol. 15: 607–660. doi:10.1146/annurev.cellbio.15.1.607. PMID 10611974.
A review article about nuclear transport, explains the principles of the mechanism, and the various transport pathways
Lamond, Angus I.; Earnshaw, WC (1998-04-24). "Structure and Function in the Nucleus" (PDF). Science. 280 (5363): 547–553. doi:10.1126/science.280.5363.547. PMID 9554838.
A review article about the nucleus, explaining the structure of chromosomes within the organelle, and describing the nucleolus and other subnuclear bodies
Pennisi E. (2004). "Evolutionary biology. The birth of the nucleus". Science. 305 (5685): 766–768. doi:10.1126/science.305.5685.766. PMID 15297641.
A review article about the evolution of the nucleus, explaining a number of different theories
Pollard, Thomas D.; William C. Earnshaw (2004). Cell Biology. Philadelphia: Saunders. ISBN 0-7216-3360-9.
A university level textbook focusing on cell biology. Contains information on nucleus structure and function, including nuclear transport, and subnuclear domains
External links
Wikimedia Commons has media related to Cell nucleus.
MBInfo - The Nucleus
cellnucleus.com Website covering structure and function of the nucleus from the Department of Oncology at the University of Alberta.
http://npd.hgu.mrc.ac.uk/user/?page=compartment The Nuclear Protein Database] Information on nuclear components.
The Nucleus Collection in the Image & Video Library of The American Society for Cell Biology contains peer-reviewed still images and video clips that illustrate the nucleus.
Nuclear Envelope and Nuclear Import Section from Landmark Papers in Cell Biology, Joseph G. Gall, J. Richard McIntosh, eds., contains digitized commentaries and links to seminal research papers on the nucleus. Published online in the Image & Video Library of The American Society for Cell Biology
Cytoplasmic patterns generated by human antibodies
[show]
v
t
e
Structures of the cell / organelles (TH H1.00.01.2-3)
Endomembrane system
Cell membrane
Nucleus
Nucleolus
Endoplasmic reticulum
Golgi apparatus
Parenthesome
Autophagosome
Vesicles
Exosome
Lysosome
Endosome
Phagosome
Vacuole
Acrosome
Cytoplasmic granules
Melanosome
Microbody
Glyoxysome
Peroxisome
Weibel–Palade body
Cytoskeleton
Microfilaments
Intermediate filaments
Microtubules
Prokaryotic cytoskeleton
MTOCs
Centrosome
Centriole
Basal body
Spindle pole body
Myofibril
Endosymbionts
Mitochondrion
Plastids
Chloroplast
Chromoplast
Gerontoplast
Leucoplast
Amyloplast
Elaioplast
Proteinoplast
Tannosome
Other internal
RNA
Ribosome
Spliceosome
Vault
Cytoplasm
Proteasome
External
Undulipodium
Cilium
Flagellum
Axoneme
Radial spoke
Extracellular matrix
Cell wall
[show]
v
t
e
Structures of the cell nucleus / nuclear protein
Envelope (membrane)/
nuclear lamina
Pore complex:
Nucleoporin
NUP35
NUP37
NUP43
NUP50
NUP54
NUP62
NUP85
NUP88
NUP93
NUP98
NUP107
NUP133
NUP153
NUP155
NUP160
NUP188
NUP205
NUP210
NUP214
AAAS
Nucleolus
Cajal (coiled) body
SMN
GEMIN2
GEMIN4
GEMIN5
GEMIN6
GEMIN7
DDX20
COIL
Perinucleolar compartment
PTBP1
CUGBP1
TCOF
ATXN7
Other
Chromatin
Dot (PML body)
Paraspeckle
SMC protein:
Cohesin
SMC1A
SMC1B
SMC3
Condensin
NCAPD2
NCAPD3
NCAPG
NCAPG2
NCAPH
NCAPH2
SMC2
SMC4
DNA repair
SMC5
SMC6
Transition nuclear protein:
TNP1
TNP2
Nuclear matrix (Nucleoskeleton)
Nucleoplasm (Nucleosol)
LITAF
see also transcription factors and intracellular receptors
see also nucleus diseases
Authority control
GND: 4067544-0
NDL: 00569971
Retrieved from "https://en.wikipedia.org/w/index.php?title=Cell_nucleus&oldid=811624751"
Categories:
Cell nucleus
Cell anatomy
Organelles
Hidden categories:
CS1 maint: Uses authors parameter
All articles lacking reliable references
Articles lacking reliable references from October 2016
All articles with dead external links
Articles with dead external links from September 2016
Articles with permanently dead external links
Webarchive template wayback links
Wikipedia pages semi-protected against vandalism
Articles which use infobox templates with no data rows
Articles containing Latin-language text
Featured articles
Wikipedia articles with GND identifiers
Navigation menu
Personal tools
Not logged in
Talk
Contributions
Create account
Log in
Namespaces
Article
Talk
Variants
Views
Read
View source
View history
More
Search
Navigation
Main page
Contents
Featured content
Current events
Random article
Donate to Wikipedia
Wikipedia store
Interaction
Help
About Wikipedia
Community portal
Recent changes
Contact page
Tools
What links here
Related changes
Upload file
Special pages
Permanent link
Page information
Wikidata item
Cite this page
Print/export
Create a book
Download as PDF
Printable version
In other projects
Wikimedia Commons
Languages
Afrikaans
Alemannisch
العربية
Aragonés
Asturianu
Azərbaycanca
বাংলা
Bân-lâm-gú
Беларуская
Беларуская (тарашкевіца)
Български
Bosanski
Català
Čeština
Cymraeg
Dansk
Davvisámegiella
Deutsch
Eesti
Ελληνικά
Español
Esperanto
Euskara
فارسی
Français
Gaeilge
Gaelg
Galego
客家語/Hak-kâ-ngî
한국어
Հայերեն
हिन्दी
Hrvatski
Bahasa Indonesia
Interlingua
Íslenska
Italiano
עברית
Basa Jawa
ಕನ್ನಡ
ქართული
Қазақша
Kiswahili
Kreyòl ayisyen
Kurdî
Кыргызча
Latina
Latviešu
Lëtzebuergesch
Lietuvių
Limburgs
Magyar
Македонски
മലയാളം
Bahasa Melayu
Nederlands
日本語
Norsk
Norsk nynorsk
Occitan
Oromoo
Oʻzbekcha/ўзбекча
پنجابی
Plattdüütsch
Polski
Português
Română
Русский
Scots
Simple English
Slovenčina
Slovenščina
کوردی
Српски / srpski
Srpskohrvatski / српскохрватски
Basa Sunda
Suomi
Svenska
Tagalog
தமிழ்
తెలుగు
ไทย
Türkçe
Українська
اردو
Tiếng Việt
Winaray
ייִדיש
粵語
中文
Edit links
This page was last edited on 22 November 2017, at 21:04.
Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.
Privacy policy
About Wikipedia
Disclaimers
Contact Wikipedia
Developers
Cookie statement
Mobile view
Enable previews

value: mw-page-base noprint

value: mw-head-base noprint

value: This is a featured article. Click here for more information.

value: mw-indicator-featured-star mw-indicator

value: This article is semi-protected due to vandalism

value: mw-indicator-pp-default mw-indicator

value: firstHeading firstHeading en

value: siteSub noprint

value: jump-to-nav mw-jump

attr: href class

attr: href class title

value: text-align:center;font-size:125%;font-weight:bold;background: rgba(0,0,0,0.1); padding: 5px; width: 290px;

value:
/wiki/Animal_cell
mw-redirect
Animal cell

value: text-align:center;font-weight:bold; font-size:125%; background-color: #0073CF; color: #FFF;

value:
/wiki/Rough_endoplasmic_reticulum
mw-redirect
Rough endoplasmic reticulum

value:
/wiki/Smooth_endoplasmic_reticulum
mw-redirect
Smooth endoplasmic reticulum

value: text-align:left; padding: 10px; background: rgba(0,0,0,0.02);

value: width:22em;width: 300px; padding: 0; border-collapse:collapse; background:transparent;

value:
/wiki/Multiprotein_complex
mw-redirect
Multiprotein complex

value:
/wiki/Eukaryotic_Nuclear_Organization
mw-redirect
Eukaryotic Nuclear Organization

value:
/wiki/Nuclear_envelope
mw-redirect
Nuclear envelope

value: Robert Brown (Scottish botanist from Montrose)

value:
/wiki/Matthias_Schleiden
mw-redirect
Matthias Schleiden

value:
/wiki/Nuclear_pores
mw-redirect
Nuclear pores

value:
/wiki/Atomic_mass_unit
mw-redirect
Atomic mass unit

value:
/wiki/Molecular_weight
mw-redirect
Molecular weight

value:
/wiki/Intermediate_filaments
mw-redirect
Intermediate filaments

value:
/wiki/Fluorescence_microscopy
mw-redirect
Fluorescence microscopy

value:
/wiki/Tetramer_protein
mw-redirect
Tetramer protein

value:
/wiki/Fluorescent_in_situ_hybridization
mw-redirect
Fluorescent in situ hybridization

attr: alt src width height class data-file-width data-file-height

value:
/wiki/Electron_micrograph
mw-redirect
Electron micrograph

value:
/wiki/Nucleolar_organizer_regions
mw-redirect
Nucleolar organizer regions

value:
/wiki/Survival_of_motor_neuron_protein
mw-redirect
Survival of motor neuron protein

value:
/wiki/Interchromatin_granules
mw-redirect
Interchromatin granules

value:
/wiki/Transcription_(genetics)
mw-redirect
Transcription (genetics)

value:
/wiki/Translation_(genetics)
mw-redirect
Translation (genetics)

value:
/wiki/Gene_regulation
mw-redirect
Gene regulation

value:
/wiki/Nuclear_localisation_signal
mw-redirect
Nuclear localisation signal

value:
/wiki/Gene_transcription
mw-redirect
Gene transcription

value:
/wiki/Primary_structure
mw-redirect
Primary structure

value:
/wiki/Ran_(biology)
mw-redirect
Ran (biology)

value:
/wiki/Nuclear_localization_signal
mw-redirect
Nuclear localization signal

value:
/wiki/Staining_(biology)
mw-redirect
Staining (biology)

value:
/wiki/Mitotic_spindle
mw-redirect
Mitotic spindle

value:
/wiki/Closed_mitosis
mw-redirect
Closed mitosis

value:
/wiki/Sister_chromatid
mw-redirect
Sister chromatid

value:
/wiki/Intestinal_parasite
mw-redirect
Intestinal parasite

value:
/wiki/Giant_multinucleated_cell
mw-redirect
Giant multinucleated cell

value:
/wiki/Evolution_of_sex
mw-redirect
Evolution of sex

value:
/wiki/PubMed_Identifier
mw-redirect
PubMed Identifier

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/6364846

value:
nofollow
external text
//doi.org/10.1038%2F254109a0

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/1117994

value:
nofollow
external text
//doi.org/10.1083%2Fjcb.149.5.1027

attr: alt src title width height srcset data-file-width data-file-height

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/10831607

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/15702987

value:
nofollow
external text
//doi.org/10.1006%2Fjsbi.1998.3987

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/9724605

value:
nofollow
external text
//doi.org/10.1083%2Fjcb.119.4.725

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/1429833

value:
nofollow
external text
//doi.org/10.1101%2Fgad.960502

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/11877373

value:
nofollow
external text
//doi.org/10.1083%2Fjcb.151.6.1155

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/11121432

value:
nofollow
external text
//doi.org/10.1083%2Fjcb.200112047

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/11854306

value: Category:CS1 maint: Uses authors parameter

value:
nofollow
external text
//doi.org/10.1016%2Fj.ceb.2004.03.009

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/15145358

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/15182349

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/16506096

value:
nofollow
external text
//doi.org/10.1007%2FBF00388452

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/2416668

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/9554838

value:
nofollow
external text
//doi.org/10.1083%2Fjcb.135.5.1195

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/8947544

value:
nofollow
external text
//doi.org/10.1172%2FJCI105669

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/4168731

value:
nofollow
external text
//doi.org/10.1212%2FWNL.45.2.384

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/7854544

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/16328431

value:
nofollow
external text
//doi.org/10.1016%2Fj.cub.2003.10.012

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/14588256

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/16212489

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/11368755

value: The material near this tag may rely on an unreliable source. (October 2016)

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/9132135

value:
nofollow
external text
//doi.org/10.1086%2F301992

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/9683623

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/9671224

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/15164213

value: Journal of Cellular Biology (page does not exist)

value:
nofollow
external text
//doi.org/10.1083%2Fjcb.115.4.919

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/1955462

value:
nofollow
external text
//doi.org/10.1093%2Femboj%2F17.6.1768

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/9501098

value:
nofollow
external text
//doi.org/10.1101%2Fcshperspect.a000661

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/20452955

value:
nofollow
external text
//doi.org/10.1038%2Fnrm1172

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/12923522

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/19005234

value:
nofollow
external text
//doi.org/10.1016%2Fj.tcb.2005.11.005

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/16325406

value:
nofollow
external text
//doi.org/10.1091%2Fmbc.10.12.4385

value:
nofollow
external text
//www.worldcat.org/issn/1059-1524

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/10588665

value:
nofollow
external text
//doi.org/10.1038%2Fnrm2124

value:
nofollow
external text
//www.worldcat.org/issn/1471-0072

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/17318225

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/11790299

value:
nofollow
external text
//doi.org/10.1091%2Fmbc.E05-06-0587

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/16148043

value:
nofollow
external text
//doi.org/10.1084%2Fjem.20062611

value:
nofollow
external text
//www.worldcat.org/issn/0022-1007

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/17954568

value:
nofollow
external text
//doi.org/10.1101%2Fcshperspect.a000703

value:
nofollow
external text
//www.worldcat.org/issn/1943-0264

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/20610547

value:
nofollow
external text
//doi.org/10.1186%2Fs12860-017-0136-x

value:
nofollow
external text
//www.worldcat.org/issn/1471-2121

value:
nofollow
external text
//doi.org/10.1042%2FBST0330265

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/15667322

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/10611974

value:
nofollow
external text
//doi.org/10.1038%2F416031a

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/11882878

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/7549180

value:
nofollow
external text
//doi.org/10.1083%2Fjcb.153.3.621

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/11331311

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/5422968

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/10708974

value:
nofollow
external text
//doi.org/10.1007%2Fbf00496738

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/7141888

value:
nofollow
external text
//doi.org/10.1073%2Fpnas.94.21.11411

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/9326623

value:
nofollow
external text
//doi.org/10.3852%2Fmycologia.98.2.233

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/16894968

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/1779932

value:
nofollow
external text
//doi.org/10.1084%2Fjem.167.2.598

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/3258008

value:
nofollow
external text
//doi.org/10.1172%2FJCI112838

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/3027126

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/22916303

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/15297641

value:
nofollow
external text
//doi.org/10.1002%2Fbies.20413

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/16615090

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/15910279

value:
nofollow
external text
//doi.org/10.1073%2Fpnas.032658599

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/11805300

value:
nofollow
external text
//doi.org/10.1007%2Fs002390010215

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/11523012

value:
nofollow
external text
//doi.org/10.1007%2Fs002390010171

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/11443345

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/10888648

value:
nofollow
external text
//doi.org/10.1016%2Fj.jtbi.2006.05.015

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/16846615

value:
nofollow
external text
//doi.org/10.1162%2Fartl.2006.12.4.513

value:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/16953783

value:
plainlist
padding:0 0.1em 0.4em;text-align:left;

value: float:right;clear:right;width:auto;margin:0 0 1.0em 1.0em;background:#f9f9f9;border:1px solid #aaa;padding:0.2em;border-spacing:0.4em 0;text-align:center;line-height:1.4em;font-size:88%

value:
nofollow
http://cellimages.ascb.org/
external text

value:
nofollow
http://www.ascb.org/
external text

value: nowraplinks hlist collapsible autocollapse navbox-inner

value:
/wiki/AAAS_(gene)
mw-redirect
AAAS (gene)

value: Template:Transcription factors and intracellular receptors

value: nowraplinks collapsible autocollapse navbox-inner

value:
nofollow
external text
https://d-nb.info/gnd/4067544-0

value: Category:All articles lacking reliable references

value: Category:Articles lacking reliable references from October 2016

value: Category:All articles with dead external links

value: Category:Articles with dead external links from September 2016

value: Category:Articles with permanently dead external links

value: Category:Webarchive template wayback links

value: Category:Wikipedia pages semi-protected against vandalism

value: Category:Articles which use infobox templates with no data rows

value: Category:Articles containing Latin-language text

value: Category:Wikipedia articles with GND identifiers

value: Discussion about edits from this IP address [ctrl-alt-n]

value: A list of edits made from this IP address [ctrl-alt-y]

value: You are encouraged to create an account and log in; however, it is not mandatory

value: You're encouraged to log in; however, it's not mandatory. [ctrl-alt-o]

value:
/wiki/Cell_nucleus
View the content page [ctrl-alt-c]
c

value:
This page is protected.
You can view its source [ctrl-alt-e]

value: Guidance on how to use and edit Wikipedia

value: About the project, what you can do, where to find things

value: A list of recent changes in the wiki [ctrl-alt-r]

value: portal navigation p-interaction p-interaction-label

value: List of all English Wikipedia pages containing links to this page [ctrl-alt-j]

value: Recent changes in pages linked from this page [ctrl-alt-k]

value:
/wiki/Wikipedia:File_Upload_Wizard
Upload files [ctrl-alt-u]
u

value: A list of all special pages [ctrl-alt-q]

value: Permanent link to this revision of the page

value: Link to connected data repository item [ctrl-alt-g]

value: Printable version of this page [ctrl-alt-p]

value: portal navigation p-wikibase-otherprojects p-wikibase-otherprojects-label

value:
uls-settings-trigger
Language settings
0
button
true

value:
https://af.wikipedia.org/wiki/Selkern
Selkern – Afrikaans
af
af
interlanguage-link-target

value:
https://als.wikipedia.org/wiki/Zellkern
Zellkern – Alemannisch
als
als
interlanguage-link-target

value: نواة (خلية) – Arabic

value: কোষ নিউক্লিয়াস – Bangla

value: Клетачнае ядро – Belarusian

value: Ядро вузы – Belarusian (Taraškievica orthography)

value: Клетъчно ядро – Bulgarian

value: interlanguage-link interwiki-ca badge-Q17437796 badge-featuredarticle

value:
https://de.wikipedia.org/wiki/Zellkern
Zellkern – German
de
de
interlanguage-link-target

value:
https://et.wikipedia.org/wiki/Rakutuum
Rakutuum – Estonian
et
et
interlanguage-link-target

value: Κυτταρικός πυρήνας – Greek

value: interlanguage-link interwiki-es badge-Q17437798 badge-goodarticle

value: هسته یاخته – Persian

value: interlanguage-link interwiki-gl badge-Q17437796 badge-featuredarticle

value: Բջջակորիզ – Armenian

value: केन्द्रक – Hindi

value:
https://id.wikipedia.org/wiki/Inti_sel
Inti sel – Indonesian
id
id
interlanguage-link-target

value: גרעין התא – Hebrew

value:
https://jv.wikipedia.org/wiki/Inti_sel
Inti sel – Javanese
jv
jv
interlanguage-link-target

value: ಜೀವಕಣದ ಬೀಜಕಣ – Kannada

value: უჯრედის ბირთვი – Georgian

value: Жасуша ядросы – Kazakh

value:
https://ku.wikipedia.org/wiki/Dendik
Dendik – Kurdish
ku
ku
interlanguage-link-target

value: Ядро (биология) – Kyrgyz

value:
https://li.wikipedia.org/wiki/Celkern
Celkern – Limburgish
li
li
interlanguage-link-target

value:
https://hu.wikipedia.org/wiki/Sejtmag
Sejtmag – Hungarian
hu
hu
interlanguage-link-target

value: interlanguage-link interwiki-hu badge-Q17437796 badge-featuredarticle

value: Клеточно јадро – Macedonian

value: കോശമർമ്മം – Malayalam

value:
https://nl.wikipedia.org/wiki/Celkern
Celkern – Dutch
nl
nl
interlanguage-link-target

value:
https://nds.wikipedia.org/wiki/Zellkarn
Zellkarn – Low German
nds
nds
interlanguage-link-target

value: interlanguage-link interwiki-pt badge-Q17437796 badge-featuredarticle

value: Клеточное ядро – Russian

value: interlanguage-link interwiki-ru badge-Q17437796 badge-featuredarticle

value:
https://fi.wikipedia.org/wiki/Tuma
Tuma – Finnish
fi
fi
interlanguage-link-target

value: உயிரணுக் கரு – Tamil

value: కణ కేంద్రకం – Telugu

value: นิวเคลียสของเซลล์ – Thai

value: Клітинне ядро – Ukrainian

value: مرکز (خلیہ) – Urdu

value: צעל יאדער – Yiddish

value: mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject page-Cell_nucleus rootpage-Cell_nucleus skin-vector action-view