Nucleohyaloplasm: Difference between revisions

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=Intra-nuclear transport=
=Intra-nuclear transport=


The lateral speed of biological molecules in passive diffusion in water is on the order of 500 - 50 nm/sec. But in cytosol such as the nucleohyaloplasm: ~120 - 10 nm/sec due to crowding and collisions with large molecules. In [[mammal]]ian cells, the average diameter of the nucleus is approximately 6 μm.<ref name=Alberts>{{cite book | year = 2002 | title = Molecular Biology of the Cell, Chapter 4, pages 191-234 | editor = Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, Peter Walter | publisher = Garland Science | edition = 4th}}</ref> The large amount of DNA and RNA should hinder the migration of nuclear proteins, but a protein could traverse the entire diameter of a nucleus in a matter of minutes.<ref name=Misteli>{{ cite journal |author=Misteli T |title=Protein dynamics: implications for nuclear architecture and gene expression |journal=Science. |volume=291 |issue=5505 |month=Feb |pages=843-7 |year=2001 |pmid=11225636 }}</ref>
The lateral speed of biological molecules in [[Passive transport|passive diffusion]] in water is on the order of 500 - 50 nm/sec. But in cytosol such as the nucleohyaloplasm: ~120 - 10 nm/sec due to crowding and collisions with large molecules. In [[mammal]]ian cells, the average diameter of the nucleus is approximately 6 μm.<ref name=Alberts>{{cite book | year = 2002 | title = Molecular Biology of the Cell, Chapter 4, pages 191-234 | editor = Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, Peter Walter | publisher = Garland Science | edition = 4th}}</ref> The large amount of DNA and RNA should hinder the migration of nuclear proteins, but a protein could traverse the entire diameter of a nucleus in a matter of minutes.<ref name=Misteli>{{ cite journal |author=Misteli T |title=Protein dynamics: implications for nuclear architecture and gene expression |journal=Science. |volume=291 |issue=5505 |month=Feb |pages=843-7 |year=2001 |pmid=11225636 }}</ref>


Proteins are frequently transported across the cytosol, along well-defined routes, and delivered to particular addresses. Passive diffusion cannot account for the rate, directionality, or destination of such transport. Microtubules function as tracks and the movement is propelled by motor proteins. Movement can occur in both directions and at velocities between ~5 and 3000 nm/sec.<ref name=Lodish>{{ cite book | author=Lodish H, Berk A, Zipursky SL, Matsudaira P, Baltimore D, Darnell JE |title=Molecular Cell Biology |publisher=WH Freeman and Company |location=New York | isbn=0-7167-3136-3 |year 2000 |edition=4th |url=http://www.ncbi.nlm.nih.gov/books/bv.fcgi?highlight=transport,Intracellular&rid=mcb.section.5452 }}</ref> One motor protein that localizes intracellularly to the nucleus is myosin 1F (125 kDa).<ref name=MYO1F>{{ cite web |title=GENATLAS : GENE Database MYO1F |url=http://genatlas.medecine.univ-paris5.fr/ }}</ref> It does not have a NLS. Its N terminal motor domain uses ATP and has actin binding sites.<ref name=MYO1F/>
Proteins are frequently transported across the cytosol, along well-defined routes, and delivered to particular addresses. Passive diffusion cannot account for the rate, directionality, or destination of such transport. [[Microtubule]]s function as tracks and the movement is propelled by [[motor protein]]s. Movement can occur in both directions and at velocities between ~5 and 3000 nm/sec.<ref name=Lodish>{{ cite book | author=Lodish H, Berk A, Zipursky SL, Matsudaira P, Baltimore D, Darnell JE |title=Molecular Cell Biology |publisher=WH Freeman and Company |location=New York | isbn=0-7167-3136-3 |year 2000 |edition=4th |url=http://www.ncbi.nlm.nih.gov/books/bv.fcgi?highlight=transport,Intracellular&rid=mcb.section.5452 }}</ref> One motor protein that localizes intracellularly to the nucleus is myosin 1F ({{Gene|MYO1F}}) 125 kDa.<ref name=MYO1F>{{ cite web |title=GENATLAS : GENE Database MYO1F |url=http://genatlas.medecine.univ-paris5.fr/ }}</ref> It does not have a NLS. Its N terminal motor domain uses ATP and has actin binding sites.<ref name=MYO1F/>


All Cajal bodies move through the nucleohyaloplasm.<ref name=Platani>{{ cite journal |author=Platani M, Goldberg I, Swedlow JR, Lamond AI |title=In Vivo Analysis of Cajal Body Movement, Separation, and Joining in Live Human Cells |journal=J Cell Biol. |volume=151 |issue=7 |pages=1561-74 |year=2000 |month=Dec |doi=10.1083/jcb.151.7.1561 |pmid= 11134083 }}</ref> These movements include translocations and moving to or from the nucleolus at velocities of ~10-15 nm/sec.<ref name=Platani/>
All Cajal bodies move through the nucleohyaloplasm.<ref name=Platani>{{ cite journal |author=Platani M, Goldberg I, Swedlow JR, Lamond AI |title=In Vivo Analysis of Cajal Body Movement, Separation, and Joining in Live Human Cells |journal=J Cell Biol. |volume=151 |issue=7 |pages=1561-74 |year=2000 |month=Dec |doi=10.1083/jcb.151.7.1561 |pmid= 11134083 }}</ref> These movements include translocations and moving to or from the nucleolus at velocities of ~10-15 nm/sec.<ref name=Platani/>


Constrained microstructures (~40-100 nm in size, on the order of 0.5-5 [[Atomic mass unit|MDa]]) move with velocities averaging 50-70 nm/sec (comparable to that of mobile chromatin), but free-moving microstructures (in chromatin-free channels) can move at speeds of up to 500 nm/sec.<ref name=Eskiw>{{ cite journal |author=Eskiw CH, Dellaire G, Mymryk JS, Bazett-Jones DP |title=Size, position and dynamic behavior of PML nuclear bodies following cell stress as a paradigm for supramolecular trafficking and assembly |journal=J Cell Sci. |volume=116 |issue=Pt 21 |month=Nov |pages=4455-66 |year=2003 |doi=10.1242/jcs.00758 |pmid= 13130097 }}</ref> The movement of PML-containing microstructures is energy-independent.<ref name=Eskiw/> Such mobility is characteristic of constrained diffusion.<ref name=Eskiw/>
Constrained microstructures (~40-100 nm in size, on the order of 0.5-5 [[Atomic mass unit|MDa]]) move with velocities averaging 50-70 nm/sec (comparable to that of mobile chromatin), but free-moving microstructures (in chromatin-free channels) can move at speeds of up to 500 nm/sec.<ref name=Eskiw/> The movement of PML-containing microstructures is energy-independent.<ref name=Eskiw/> Such mobility is characteristic of constrained diffusion.<ref name=Eskiw/>


The movement of elongated chromosomes throughout the chromatin filled nucleus may be associated with intranuclear motor protein action.<ref name=Scherthan>{{ cite book |author=Scherthan H, Orr-Weaver T, Arana P, Gill B |page=225 |title=Meiotic mobility and recombination |pages=215-248 |editor=Henriques-Gil N, Parker JS, Puertas MJ |proceedings title=Chromosomes Today |volume=12 |year=1997 |publisher=Springer |isbn=0412752409, 9780412752407 }}</ref>
The movement of elongated chromosomes throughout the chromatin filled nucleus may be associated with intranuclear motor protein action.<ref name=Scherthan>{{ cite book |author=Scherthan H, Orr-Weaver T, Arana P, Gill B |page=225 |title=Meiotic mobility and recombination |pages=215-248 |editor=Henriques-Gil N, Parker JS, Puertas MJ |proceedings title=Chromosomes Today |volume=12 |year=1997 |publisher=Springer |isbn=0412752409, 9780412752407 }}</ref>

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Editor-In-Chief: Henry A. Hoff

Introduction

Nucleohyaloplasm is the cytosol within the nucleus, without the microfilaments and the microtubules, also known as nucleosol, vis à vis mitosol and cytosol[1]. This liquid part contains enzymes (which direct activities that take place in the nucleus), intermediate metabolites, and many substances such as nucleotides (necessary for purposes as the replication of DNA and production of mRNA). All are dissolved in the nucleohyaloplasm.

As a cytosol, it consists mostly of water, dissolved ions, small molecules, and large water-soluble molecules (such as protein). It contains about 20% to 30% protein. It has a high concentration of K⁺ ions and a low concentration of Na⁺ ions. Normal human cytosolic pH ranges between 7.3 - 7.5, depending on the cell type involved.[2]

Small particles

Small particles (< 40 kDa[3], <50 kDa[4], <~70 kDa[5], ≤ 70 kDa[6]) are able to pass through the nuclear pore complex by passive transport. Larger proteins require a nuclear localization signal (NLS). The pores are 100 nm in total diameter, with an opening diameter of about 50 nm; however, the gap through which molecules freely diffuse is only about 9-10 nm wide,[7] due to the presence of regulatory systems within the center of the pore. The 10 nm diameter corresponds to an upper mass limit of 70 kDa.[8] The majority of the non-protein molecules have a molecular mass of less than 300 Da.[9]

This mixture of small molecules is extraordinarily complex, as the variety of molecules that are involved in metabolism (the metabolites) is immense. For example up to 200,000 different small molecules might be made in plants, although not all these will be present in the same species, or in a single cell.[10] Estimates of the number of metabolites in a single cell of E. coli or baker's yeast predict that under 1,000 are made.[11][12]

Miscible molecules

Miscible molecules such as O2, CO2, N2, and NH3 occur in any bodily fluid. These molecules are mixed into the liquid, but not turned into ions. Water contains only 1/20 parts O2. N2 mixes into the bloodstream and body fats.

Inorganic ions

Relative to the outside of a cell, the concentration of Ca2+ is low.[13] In addition to sodium and potassium ions the nucleohyaloplasm also contains Mg2+[14]. Some of these magnesium ions are associated with incoming ribonucleoside triphosphate (NTP) as they enter the catalytic center for transcription by RNA polymerase (RNAP) II.[14] The remaining typical ions found in any cytosol include chloride and bicarbonate.[15]

Intranuclear posttranscriptional modifications such as mRNA editing convert cytidine to uridine within some mRNA.[16] This conversion by enzyme EC 3.5.4.5 though infrequent releases ammonia[17] or produces ammonium (NH4+) in solution. This enzyme is Zn2+ dependent. The zinc ion in the active site plays a central role in the proposed catalytic mechanism, activating a water molecule to form a hydroxide ion (OH-) that performs a nucleophilic attack on the substrate.[18]

Cells also maintain an intracellular iron ion (Fe2+) homeostasis.[19] Cu2+ serves as a cofactor.[20] Iron homeostasis involves interconversions of Fe2+ with Fe3+.

When a nucleotide is incorporated into a growing DNA or RNA strand by a polymerase, pyrophosphate (PPi) is released. The pyrophosphate anion has the structure P2O74−, and is an acid anhydride of phosphate. It is unstable in aqueous solution and in the absence of enzymic catalysis hydrolyzes extremely slowly into inorganic phosphate HPO42− (orthophosphate, Pi) in all but highly acidic media.[21]

Enzyme EC 3.6.1.1 catalyzes the hydrolysis of PPi to Pi:

PPi + H2O <=> 2 Pi.

The enzyme is Mg2+ binding, occurs in the cytosol, has a 33 kDa form, and no NLS. The enzymes of EC 3.6.1.1, in general, exist as homooligomers.

Carbohydrates

Of the carbohydrates, monosaccharides and oligosaccharides are water soluble. Polysaccharides on the other hand tend to be insoluble in water. As to alcohols, there are two opposing solubility trends: the tendency of the polar OH to promote solubility in water, and of the carbon chain to resist it. Thus, methanol, ethanol, and propanol are miscible in water because the hydroxyl group wins out over the short carbon chain. Butanol, with a four-carbon chain, is moderately soluble because of a balance between the two trends. Alcohols of five or more carbons (pentanol and higher) are effectively insoluble in water because of the hydrocarbon chain's dominance.

Fatty acids

Short chain carboxylic acids such as formic acid and acetic acid are miscible with water and dissociate to form reasonably strong acids (pKa 3.77 and 4.76, respectively). Longer-chain fatty acids do not show a great change in pKa. Nonanoic acid, for example, has a pKa of 4.96. However, as the chain length increases the solubility of the fatty acids in water decreases very rapidly, so that the longer-chain fatty acids have very little effect on the pH of a solution.

When the body uses stored fat as a source of energy, glycerol and fatty acids are released into the bloodstream. The glycerol component can be converted to glucose by the liver and provides energy for cellular metabolism.

Amino acids

The average mass range for amino acids: 75 - 222 Da. By comparison a water molecule is 18 Da. In addition to the proteinogenic standard amino acids, there are a number of other amino acids (aa) involved in the synthesis of the proteinogenic aa: citrulline (Cit), cystathionine (Cth), homocysteine (Hcy), ornithine (Orn), sarcosine (Sar) and taurine (Tau), for example. As Tau does not contain a carboxyl group it is not an aa, but since in its place it does contain a sulfonate group, it may be called an amino sulfonic acid.

Nucleobases

Purine (Pur) 120 Da is not a protein. The purines are the most widely distributed naturally occurring nitrogen-containing heterocycle.[22] The purine nucleobases include adenine (A) 135 Da, hypoxanthine (Hx) 136 Da, guanine (G) 151 Da, and xanthine (Xan) 152 Da. The pyrimidines include pyrimidine (Pyr) 80 Da, also a heterocycle and naturally occurring, cytosine (C) 111 Da, uracil (U) 112 Da, thymine (T) 126 Da, and queuine (Q) 275 Da.

Nucleosides

Nucleosides are glycosylamines, a nucleobase linked to a ribose or deoxyribose ring. Examples include purines: adenosine (Ado) 267 Da, guanosine (Guo) 283 Da, and inosine (Ino) 268 Da, and pyrimidines: cytidine (Cyd) 243 Da, thymidine (Thd) 242 Da, uridine (Urd) 244 Da, and queuosine (Quo) 409 Da. When the nucleobase is attached to deoxyribose, a 'd' is placed in front of the abbreviation, e.g., dCyd is deoxycytidine 227 Da and the molar mass decreases by one oxygen from Cyd.

Nucleotides

Nucleotides such as orotidine 5'-monophosphate (OMP) range in size from 176 Da (OMP) to 523 Da (GTP). The purine nucleotides involved in RNA or DNA synthesis include: inosine monophosphate (IMP), adenosine triphosphate (ATP), and guanosine triphosphate (GTP). The pyrimidine nucleotides involved include OMP, cytidine triphosphate (CTP), uridine triphosphate (UTP), and thymidine triphosphate (TTP) for DNA in place of UTP. Although rare, higher phosphates do occur such as adenosine tetraphosphate (Ap4) 587 Da. The deoxyribonucleotides have a 'd' in front, like dCTP, except for the thymidine deoxyribonucleotides.

Cofactors

Many cofactors are involved in the synthesis of amino acids and nucleotides. They range in size from ascorbic acid (ASA) 176 Da and biotin (BIO) 244 Da, which are vitamins, to nicotinamide adenine dinucleotide phosphate (NADP) 744 Da and flavin adenine dinucleotide (FAD) 785 Da.

One of the coenzymes essential for the synthesis of amino acids is nicotinamide adenine dinucleotide (NAD) 663 Da. Besides assembling NAD+ de novo from simple amino acid precursors, cells also salvage preformed compounds containing nicotinamide. The three natural compounds containing the nicotinamide ring and used in these salvage metabolic pathways are nicotinic acid (Na), nicotinamide (Nam) and nicotinamide riboside (NR).[23] These compounds are also produced within cells, when the nicotinamide group is released from NAD+ in ADP-ribose transfer reactions. Indeed, the enzymes involved in these salvage pathways appear to be concentrated in the cell nucleus, which may compensate for the high level of reactions that consume NAD+ in this organelle.[24] Nicotinamide mononucleotide adenylyl transferase 1 (NMNAT1) (EC 2.7.7.1) catalyzes a key step of NAD synthesis.[25] It has a nuclear localization signal (NLS).[25] NMNAT1 may be a substrate for nuclear kinases.[25]

Peptides

Peptides are short polymers formed from the linking, in a defined order, of α-amino acids. Proteins are polypeptide molecules (or consist of multiple polypeptide subunits). The distinction is that peptides are short and polypeptides/proteins are long. The digestion of dietary proteins produces dipeptides which are absorbed more rapidly than aa. A dipeptide is a molecule consisting of two amino acids joined by a single peptide bond. Examples of dipeptides include carnosine (Car) 244 Da, of the amino acids β-alanine (β-Ala) and histidine (His), homocarnosine (Hcn) 258 Da consisting of γ-aminobutyric acid (GABA) and His, and anserine (Ans) 240 Da.

Oligopeptides

Some tripeptides and tetrapeptides are synthesized in humans. Oligopeptides can range up to 40 aa (9 kDa) generally.

Small proteins (polypeptides)

Due to the size limitation of the nuclear pore, these polypeptides would range from 9 kDa to <70 kDa and not need or have a NLS. For example, emerin 18 kDa (no NLS) mediates inner nuclear membrane anchorage to the nuclear lamina, regulates the flux of beta-catenin into the nucleus, and interacts with nuclear actin.[26][27][28]

On the other hand, LEMD1 (20.3 kDa) is involved in the glutamine (Gln) metabolic process[29] and has a NLS.[30]

Many of the polypeptides are enzymes including peptidases and kinases.

Proteases

Carnosinase occurs as EC 3.4.13.3 (Xaa-His dipeptidase) with Zn2+ as cofactor, 3.4.13.18 (cytosol nonspecific dipeptidase) with Zn2+ as cofactor and Mn2+ activation, and 3.4.13.20 (beta-Ala-His dipeptidase), activated by Cd2+ and citrate, catalyzing the reaction

Car + H2O <=> His + β-Ala.

It is intracellular to the cytosol and can occur in 14 kDa, 35 kDa, and 44 kDa sizes, often forming a homodimer. As a nonspecific dipeptidase, it degrades a number of dipeptides including Car[31], Ans and Hcn[31] as EC 3.4.13.3 and EC 3.4.13.20 per the reaction:

Hcn + H2O <=> γ-aminobutyric acid (GABA) + His.

Oligopeptides can be degraded by aminopeptidases such as EC 3.4.11.6 19-68 kDa forms (intracellular to the cytosol) with Zn2+ as cofactor and activation by Cl- per the reactions:

oligopeptide (n) + H2O <=> Lys + oligopeptide (n-1)

oligopeptide (n) + H2O <=> Arg + oligopeptide (n-1).

Synthases

Enzymes EC 2.3.1.37 (cofactor: pyridoxal phosphate, PLP) aminolevulinate, delta-, synthase 1 (ALAS1) and aminolevulinate, delta-, synthase 2 (ALAS2) anabolically synthesize glycine (Gly) from the amino acid 5-amino-4-oxovaleric acid (ALA) in the two-step reaction:

5-aminolevulinate (C5H9NO3) (ALA) + CO2 <=> 2-amino-3-oxoadipate (C6H9NO5)

+

2-amino-3-oxoadipate + CoA (C21H36N7O16P3S) <=> succinyl-CoA (C25H40N7O19P3S) + Gly

=

5-aminolevulinate + CoA + CO2 <=> succinyl-CoA + Gly

The mRNA for ALAS1 is 82 kDa, the intracellular precursor is a homodimer of 71 kDa, and the mitochondrial mature protein is 65 kDa. But, ALAS1 also occurs in a 30 kDa form.[32]

CTP synthase EC 6.3.4.2 is the final step in the de novo synthesis of CTP from UTP. As a monomer 67 kDa or dimer it is inactive because three monomers contribute to ligand binding at the active site.[33] The active form is a homotetramer (a dimer of dimers), with no NLS, intracellular to the cytosol,[33][34] for the following reactions.

UTP + Gln + ATP + H2O <=> CTP + Glu + ADP + Pi

ATP + UTP + NH3 <=> ADP + Pi + CTP

The reactions

2 ATP + HCO3- + NH3 <=> 2 ADP + Pi + carbamoyl phosphate (multistep)[35]

Gln + H2O <=> Glu + NH3[36]

2 ADP + Pi + Glu + carbamoyl phosphate <=> 2 ATP + Gln + HCO3- + H2O[37]

are catalyzed by EC 6.3.5.5 carbamoyl-phosphate synthase II (CAD). It has no NLS, occurs as a homohexamer, uses Zn2+ as a cofactor and is intracellular to the nucleus.[38] It does occur in a 22 kDa form.[39]

Polymerases

Many of the subunits of RNA polymerase II (EC 2.7.7.6) are small polymerases. RNA polymerase IIC (PolR2C) has a mass of 33 kDa, no NLS, is intracellular to the nucleus and is part of the transcription complex. Of the others, PolR2D-L are 19 kDa or less without NLS, except RNA polymerase IIE (PolR2E) 23 kDa has a NLS and is the only one that localizes to the nucleolus.[40] Although PolR2K and PolR2L are small enough in mass to be considered oligopeptides, their numbers of aa are over the usual limit: 58 aa and 67 aa, respectively, in humans.

Kinases

EC 3.6.1.5 (cofactor: Ca2+) catalyzes the following reactions:

AMP + Pi <=> ADP + H2O

AMP + 2 Pi <=> ATP + 2 H2O

ADP + Pi <=> ATP + H2O

CMP + Pi <=> CDP + H2O

CMP + 2 Pi <=> CTP + 2 H2O

CDP + Pi <=> CTP + H2O

GMP + Pi <=> GDP + H2O

GMP + 2 Pi <=> GTP + 2 H2O

GDP + Pi <=> GTP + H2O

UMP + Pi <=> UDP + H2O

UMP + 2 Pi <=> UTP + 2 H2O

UDP + Pi <=> UTP + H2O

Ca2+ or Mg2+ can serve as activating ions. ENTPD1 (CD39) is a 56 kDa protein.[41] CD39 associates with RanBPM (RANBP9).[42] RANBP9 (90 kDa)[43] binds Ran, a small GTP binding protein that is essential for the translocation of RNA and proteins through the nuclear pore complex.[44] RanBPM localizes in the nucleus and cytoplasm,[42] but RanBPM has no NLS. CANT1 (EC 3.6.1.6 and 3.6.1.5) 49 kDa[45] catalyzes similar reactions:

a nucleotide + Pi <=> a nucleoside diphosphate + H2O,

also acting on IDP, GDP, UDP and on D-ribose 5-diphosphate.[46] ENTPD7 (EC 3.6.1.-) occurs in the mouse nucleus.[47]

Enzymes 2.4.2.7 adenine phosphoribosyltransferase (APRT) 19.4 kDa (forms a dimer, 38.8 kDa) is intracellular (cytoplasm)[48] and 2.4.2.8 hypoxanthine phosphoribosyltransferase 1 (HPRT1) 24 kDa (forms a tetramer, 96 kDa) is intracellular (cytosolic)[49] catalyze the following reaction:

Adenine + 5-phospho-alpha-D-ribose 1-diphosphate (PRPP) <=> AMP + PPi

Neither APRT nor HPRT1 has a NLS. APRT is a dimer in solution at pH 6.5, but a monomer at pH 8.0, and like HPRT1 needs Mg2+, or Mn2+.[50]

Enzymes EC 3.6.1.5 ATP pyrophosphohydrolase, ADPase[51]/ADP synthase[52] ectonucleoside triphosphate diphosphohydrolase 1 (ENTPD1) 56 kDa catalyzes the conversion of AMP into ADP (see below). Cofactor: Ca2+.[53] Ca2+ or Mg2+ can serve as activating ions. Also acts on ADP, and on other nucleoside triphosphates and diphosphates.[53]

AMP + Pi <=> ADP + H2O

Enzymes EC 2.7.4.6 nucleoside-diphosphate kinases A, B, C, D (NDKA-D) catalyzes the following reaction inside the nucleohyaloplasm as it is intracellular (nucleus)[54] and each gene is translated as a 7-11 kDa particle[55]. However, these kinases exist either as tetramers (28-44 kDa) in bacteria or hexamers (42-66 kDa).[56] Once the hexamer has formed the particle may be too big to pass through the nuclear pores. NDKA has been shown to mediate transcription, associate with a promoter region of a gene, and be a member of the SET or INHAT complex which can modulate gene expression.[57] Nucleoside-diphosphate kinase does form nuclear and cytoplasmic hexamers.[58] NDKA-D do not have a NLS.

ADP + GTP <=> ATP + GDP

Transaminases

In catabolic transamination, with PLP as a cofactor, EC 2.6.1.2 transfers the amine from glutamic acid (glutamate) (Glu) to alanine (Ala) via a two step reaction:

PLP + Glu <=> pyridoxamine monophosphate (PMP) + α-ketoglutarate (2-oxoglutarate)

+

PMP + pyruvate <=> PLP + Ala

=

pyruvate + Glu <=> Ala + 2-oxoglutarate.

Although this enzyme has several different names, e.g., alanine transaminase, glutamic-pyruvate transaminase (GPT), or alanine aminotransferase, it can occur as a monomer of 55 kDa or homodimer of 101 kDa, and as either a cytosolic (GPT1), or mitochondrial form (GPT2).

Synthetases

The reactions

ATP + Glu + NH3 (or NH4+) <=> ADP + Pi + Gln

ATP + Asp + NH4+ <=> ADP + Pi + Asn

ATP + Asp + NH4+ <=> AMP + PPi + Asn

are catalyzed by the enzyme EC 6.3.1.2 glutamine synthetase (GS), glutamine-ammonia ligase (GLUL). GLUL 42 kDa is intracellular, occurs as a homooctamer,[59], also as 12 kDa and 22 kDa forms,[60] and complexes with phosphate, ADP, and Mn2+.

Large particles

Larger particles are also able to pass through the large diameter of a nuclear pore but at almost negligible rates.[61] However, the nucleohyaloplasm does contain large amounts of macromolecules, which can alter how molecules behave, through macromolecular crowding. Since some of these macromolecules have less volume to move in, their effective concentration is increased. This crowding effect can produce large changes in both the rates and chemical equilibrium for reactions in the nucleohyaloplasm.[62] It is particularly important in its ability to alter dissociation constants by favoring the association of macromolecules, such as when multiple proteins come together to form protein complexes, or when DNA-binding proteins bind to their targets in the genome.[63]

Proteins

Proteins larger than those allowed through a nuclear pore by passive transport require a nuclear localization signal (NLS). This is an amino acid sequence that targets the cytosolic nuclear transport receptors of the nuclear pore complex. A nuclear import NLS will bind strongly to importin, while an export NLS (nuclear export signal, NES) binds to an exportin. For example, RNA polymerase IIA (Rbp1) 220kDa has a NLS.[64]

Nuclear localization

The subcellular distribution of a substance to or within the nucleus is often referred to as nuclear localization.[65] Many mechanisms have been found that produce nuclear localization in addition to a NLS.

Zac1 is a seven-zinc-finger transcription factor that preferentially binds GC-rich DNA elements and has intrinsic transactivation activity.[66] The zinc-finger motif is of a Cys2His2-type.[66] This motif is involved in DNA binding, dimerization, transactivation activity, and nuclear localization of Zac1 through interacting with importin α1.[66] Zac1 has no typical NLS.[66] Any two or more zinc-finger motifs act in concert to facilitate nuclear localization.[66] Apparently, as with importin α transport of CaMKIV to the nucleus, importin α1 may mediate transport of Zac1 to the nucleus without the involvement of importin β.[66] But, some other factors are involved, perhaps Ran-binding proteins such as RanBPM and Mog1[67], which play roles in nucleocytoplasmic transport and transcription factor recruitment.[66]

RNA

Of the many different types of RNA that can occur within a cell, most also can occur dissolved in the nucleohyaloplasm. In addition to mRNA, which is constructed during gene transcription to produce protein, there are a variety of RNAs that are transcripted from genes for their own sake into the nucleohyaloplasm: ribosomal RNA (rRNA), transfer RNA (tRNA), small nuclear RNA (snRNA), small nucleolar RNA (snRNA), non-coding RNA (ncRNA), miscRNA[68], microRNA, piwi-interacting RNA (piRNA), small interfering RNA (siRNA), signal recognition particle RNA (SRP RNA), and guide RNA (gRNA).

Ribozymes are transcripted into the nucleohyaloplasm. The functional part of the ribosome, the molecular machine that translates RNA into proteins, is fundamentally a ribozyme. Ribozymes often have divalent metal ions such as Mg2+ as cofactors. Ribozyme RNase P 30kDa has a NLS.[69] But, RNase P subunit p25 (25 kDa), which is also localized to the nucleolus does not.[70]

Probably the largest mRNA transcripted into the nucleohyaloplasm is from the gene for dystrophin (427 kDA protein). The primary transcript measures 2.4 megabases (thus the gene comprises 0.008% of the human genome), and takes 16 hours to transcribe. The 79 exons code for a protein of 3685 amino acid residues. Its mRNA is 14 kb or ~550 kDa.

Chromatin

Euchromatin is the less compact DNA form, and contains genes that are frequently expressed by the cell.[71] Active genes, which are generally found in the euchromatic region of the chromosome, tend to be located towards the chromosome's territory boundary.[72]

Heterochromatin is usually localized to the periphery of the nucleus along the nuclear envelope. It mainly consists of genetically inactive satellite sequences,[73] and many genes are repressed to various extents, although some cannot be expressed in euchromatin at all.[74]

Mobile chromatin

During interphase euchromatin is known to be attached to the nucleolus or nucleoli and heterochromatin is attached to the nuclear envelope.[75] Further, in some cell types interphase euchromatin and heterochromatin are translationally immobile over distances ≥400 nm.[75] Mobile chromatin can move with velocities averaging 50-70 nm/sec.[76]

Nucleolus

The nucleolus is roughly spherical, and is surrounded by the euchromatin. No membrane separates the nucleolus from the nucleohyaloplasm. Nucleoli carry out the production and maturation of ribosomes. Large numbers of ribosomes are found inside.

Direct contact between the nucleolus and the nuclear envelope is frequently observed but is not dependent on nucleolar activity.[77]

Although the size of the nucleolus is highly variable in any particular cell nucleus, there is in some cells a correlation with cell diameter: increasing cell size to increasing rounded diameter of the nucleolus.[78] Based on this correlation, for an average mammalian cell of 6000 nm, the nucleolus would be ~300 nm in diameter. Interferometric analysis of nucleolus mass for mesothelial cells in culture places its mass average at 40 x 10-12 gm (40 pgm)[79] or approximately 24 TDa (teradaltons). In addition, each cell may have approximately the same total nucleolar mass regardless of the number of nucleoli.[79]

Structures

Of the structures local to the nucleohyaloplasm, some serve to confine it such as the inner membrane of the nuclear envelope. While others are completely suspended within it, for example, the nucleolus. Still others such as the nuclear matrix[80][81] and nuclear lamina are found throughout the inside of the nucleus, some as part of the nucleoskeleton.

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 nucleohyaloplasm is not a uniform mixture, but rather contains organized functional subdomains.[82]

Intra-nuclear transport

The lateral speed of biological molecules in passive diffusion in water is on the order of 500 - 50 nm/sec. But in cytosol such as the nucleohyaloplasm: ~120 - 10 nm/sec due to crowding and collisions with large molecules. In mammalian cells, the average diameter of the nucleus is approximately 6 μm.[83] The large amount of DNA and RNA should hinder the migration of nuclear proteins, but a protein could traverse the entire diameter of a nucleus in a matter of minutes.[84]

Proteins are frequently transported across the cytosol, along well-defined routes, and delivered to particular addresses. Passive diffusion cannot account for the rate, directionality, or destination of such transport. Microtubules function as tracks and the movement is propelled by motor proteins. Movement can occur in both directions and at velocities between ~5 and 3000 nm/sec.[15] One motor protein that localizes intracellularly to the nucleus is myosin 1F (MYO1F) 125 kDa.[85] It does not have a NLS. Its N terminal motor domain uses ATP and has actin binding sites.[85]

All Cajal bodies move through the nucleohyaloplasm.[86] These movements include translocations and moving to or from the nucleolus at velocities of ~10-15 nm/sec.[86]

Constrained microstructures (~40-100 nm in size, on the order of 0.5-5 MDa) move with velocities averaging 50-70 nm/sec (comparable to that of mobile chromatin), but free-moving microstructures (in chromatin-free channels) can move at speeds of up to 500 nm/sec.[76] The movement of PML-containing microstructures is energy-independent.[76] Such mobility is characteristic of constrained diffusion.[76]

The movement of elongated chromosomes throughout the chromatin filled nucleus may be associated with intranuclear motor protein action.[87]

Human nucleohyaloplasm

Mature monocytes circulating in human peripheral blood contain multiple nucleoli of various sizes in one and the same nucleus.[88] The nucleolar RNA content is apparently related to the nucleolar size.[88] Increases in the number of nucleoli, their size, and their activity reflect the proliferating activity of exponentially growing cells.[89]

References

  1. ↑ Solakidi S, Psarra AM, Sekeris CE (2007). "Differential distribution of glucocorticoid and estrogen receptor isoforms:localization of GRβ and ERα in nucleoli and GRα and ERβ in the mitochondria of human osteosarcoma SaOS-2 and hepatocarcinoma HepG2 cell lines" (PDF). J Musculoskelet Neuronal Interact. 7 (3): 240–5. PMID 17947807. Unknown parameter |month= ignored (help)
  2. ↑ Roos A, Boron WF (1981). "Intracellular pH". Physiol. Rev. 61 (2): 296–434. PMID 7012859. Unknown parameter |month= ignored (help)
  3. ↑ Naim B, Brumfeld V, Kapon R, Kiss V, Nevo R, Reich Z (2007). "Passive and Facilitated Transport in Nuclear Pore Complexes Is Largely Uncoupled". J Biol Chem. 282 (6): 3881–8. doi:10.1074/jbc.M608329200. PMID 17164246. Unknown parameter |month= ignored (help)
  4. ↑ "Research highlights". Biopolymers. 2007. p. fmiv. doi:10.1002/bip.20740. Unknown parameter |month= ignored (help)
  5. ↑ Mahato RI, Rolland A, Tomlinson E (1997). "Cationic Lipid-Based Gene Delivery Systems: Pharmaceutical Perspectives". Pharm Res. 14 (7): 853–9. PMID 9244140. Unknown parameter |month= ignored (help)
  6. ↑ Chesnoy S, Huang L (2000). "STRUCTURE AND FUNCTION OF LIPID-DNA COMPLEXES FOR GENE DELIVERY". Annu Rev Biophys Biomol Struct. 29: 27–47. doi:10.1146/annurev.biophys.29.1.27. PMID 10940242. Unknown parameter |month= ignored (help)
  7. ↑ Kramer A, Ludwig Y, Shahin V, Oberleithner H (2007). "A Pathway Separate from the Central Channel through the Nuclear Pore Complex for Inorganic Ions and Small Macromolecules". J Biol Chem. 282 (43): 31437–43. doi:10.1074/jbc.M703720200. PMID 17726020. Unknown parameter |month= ignored (help)
  8. ↑ Melchior F, Gerace L (1995). "Mechanisms of nuclear protein import". Curr Opin Cell Biol. 7 (3): 310–8. PMID 7662359. Unknown parameter |month= ignored (help)
  9. ↑ Goodacre R, Vaidyanathan S, Dunn WB, Harrigan GG, Kell DB (2004). "Metabolomics by numbers: acquiring and understanding global metabolite data" (PDF). Trends Biotechnol. 22 (5): 245–52. doi:10.1016/j.tibtech.2004.03.007. PMID 15109811. Unknown parameter |month= ignored (help)
  10. ↑ Weckwerth W (2003). "Metabolomics in systems biology". Annu Rev Plant Biol. 54: 669–89. doi:10.1146/annurev.arplant.54.031902.135014. PMID 14503007.
  11. ↑ Reed JL, Vo TD, Schilling CH, Palsson BO (2003). "An expanded genome-scale model of Escherichia coli K-12 (iJR904 GSM/GPR)". Genome Biol. 4 (9): R54. doi:10.1186/gb-2003-4-9-r54. PMC 193654. PMID 12952533.
  12. ↑ Förster J, Famili I, Fu P, Palsson BØ, Nielsen J (2003). "Genome-scale reconstruction of the Saccharomyces cerevisiae metabolic network". Genome Res. 13 (2): 244–53. doi:10.1101/gr.234503. PMC 420374. PMID 12566402. Unknown parameter |month= ignored (help)
  13. ↑ Berridge MJ (1997). "Elementary and global aspects of calcium signalling". J. Physiol. (Lond.). 499 ( Pt 2): 291–306. PMC 1159305. PMID 9080360. Unknown parameter |month= ignored (help)
  14. ↑ 14.0 14.1 Langelier MF, Baali D, Trinh V, Greenblatt J, Archambault J, Coulombe B (2005). "The highly conserved glutamic acid 791 of Rpb2 is involved in the binding of NTP and Mg(B) in the active center of human RNA polymerase II". Nucleic Acids Res. 33 (8): 2629–39. PMID 15886393. Unknown parameter |month= ignored (help)
  15. ↑ 15.0 15.1 Lodish, Harvey F. (1999). Molecular cell biology. New York: Scientific American Books. ISBN 0-7167-3136-3. OCLC 174431482.
  16. ↑ Ashkenas J (1997). "Gene regulation by mRNA editing". Am J Hum Genet. 60 (2): 278–83. PMID 9012400. Unknown parameter |month= ignored (help)
  17. ↑ "NiceZyme View of ENZYME: EC 3.5.4.5".
  18. ↑ "NCBI Conserved Domains: cytidine_deaminase-like Super-family".
  19. ↑ Mukhopadhyay CK, Attieh ZK, Fox PL (1998). "Role of ceruloplasmin in cellular iron uptake". Science. 279 (5351): 714–7. PMID 9445478. Unknown parameter |month= ignored (help)
  20. ↑ 1.16.3.1 "NiceZyme View of ENZYME: EC 1.16.3.1" Check |url= value (help).
  21. ↑ Huebner PWA, Milburn RM (1980). "Hydrolysis of pyrophosphate to orthophosphate promoted by cobalt(III). Evidence for the role of polynuclear species". Inorg Chem. 19 (5): 1267–72. doi:10.1021/ic50207a032. Unknown parameter |month= ignored (help)
  22. ↑ Rosemeyer, H. Chemistry & Biodiversity 2004, 1, 361.
  23. ↑ Tempel W, Rabeh WM, Bogan KL; et al. (2007). "Nicotinamide riboside kinase structures reveal new pathways to NAD+". PLoS Biol. 5 (10): e263. PMID 17914902.
  24. ↑ Anderson RM, Bitterman KJ, Wood JG; et al. (2002). "Manipulation of a nuclear NAD+ salvage pathway delays aging without altering steady-state NAD+ levels". J. Biol. Chem. 277 (21): 18881&ndash, 90. PMID 11884393.
  25. ↑ 25.0 25.1 25.2 Schweiger M, Hennig K, Lerner F, Niere M, Hirsch-Kauffmann M, Specht T, Weise C, Oei SL, Ziegler M (2001). "Characterization of recombinant human nicotinamide mononucleotide adenylyl transferase (NMNAT), a nuclear enzyme essential for NAD synthesis". FEBS Lett. 492 (1–2): 95–100. PMID 11248244. Unknown parameter |month= ignored (help)
  26. ↑ "Entrez Gene: EMD emerin".
  27. ↑ "GENATLAS: GENE Database EMD".
  28. ↑ "Apropos IpiRecord: IPI00032003".
  29. ↑ "Apropos IpiRecord: IPI00438351".
  30. ↑ "Nuclear Protein Database LEMD1".
  31. ↑ 31.0 31.1 Balion CM, Benson C, Raina PS, Papaioannou A, Patterson C, Ismaila AS (2007). "Brain type carnosinase in dementia: a pilot study". BMC Neurol. 7 (Nov 5): 38. PMID 17983474.
  32. ↑ "Apropos IpiRecord: IPI00789294 ALAS1, 30 KDA PROTEIN".
  33. ↑ 33.0 33.1 Kursula P, Flodin S, Ehn M, Hammarstrom M, Schüler H, Nordlund P, Stenmark P (2006). "Structure of the synthetase domain of human CTP synthetase, a target for anticancer therapy". Acta Crystallogr Sect F Struct Biol Cryst Commun. 62 (Pt 7): 613–7. doi:10.1107/S1744309106018136. PMID 16820675. Unknown parameter |month= ignored (help)
  34. ↑ "GENATLAS : GENE Database CTPS".
  35. ↑ "KEGG REACTION: R07641".
  36. ↑ "KEGG REACTION: R00256".
  37. ↑ "KEGG REACTION: R00575".
  38. ↑ "GENATLAS : GENE Database CAD".
  39. ↑ "Apropos IpiRecord: IPI00301263 CAD".
  40. ↑ "Nuclear Protein Database DNA-directed RNA polymerase II 23 kDa polypeptide".
  41. ↑ "Apropos IpiRecord: IPI00382672".
  42. ↑ 42.0 42.1 Wu Y, Sun X, Kaczmarek E, Dwyer KM, Bianchi E, Usheva A, Robson SC (2006). "RanBPM associates with CD39 and modulates ecto-nucleotidase activity". Biochem J. 396 (1): 23–30. PMID 16478441. Unknown parameter |month= ignored (help)
  43. ↑ "GENATLAS: GENE Database RANBP9".
  44. ↑ "Entrex Gene: RANBP9 RAN binding protein 9".
  45. ↑ "Apropos IpiRecord: IPI00413533".
  46. ↑ "NiceZyme View of ENZYME: EC 3.6.1.6".
  47. ↑ "Apropos IpiRecord: IPI00828276".
  48. ↑ "GENATLAS : GENE Database APRT".
  49. ↑ "GENATLAS : GENE Database HPRT1".
  50. ↑ Phillips CL, Ullman B, Brennan RG, Hill CP (1999). "Crystal structures of adenine phosphoribosyltransferase from Leishmania donovani". EMBO J. 18 (13): 3533–45. doi:10.1093/emboj/18.13.3533. PMID 10393170.
  51. ↑ Moodie FDL, Baum H, Peter J, Butterworth PJ, Timothy J, Peters TJ (1991). "Purification and characterisation of bovine spleen ADPase". Eur. J. Biochem. 202 (3): 1209–15. PMID 1837267. Unknown parameter |month= ignored (help)
  52. ↑ Goodman JM (2008). "The gregarious lipid droplet". J Biol Chem. 283 (42): 28005–9. doi:10.1074/jbc.R80004220. PMID 18611863. Unknown parameter |month= ignored (help)
  53. ↑ 53.0 53.1 "NiceZyme View of ENZYME: EC 3.6.1.5".
  54. ↑ "GENATLAS : GENE Database NME3".
  55. ↑ "Apropos IpiRecord: IPI00012048".
  56. ↑ "NCBI Conserved Domains cd04413: NDPK_I".
  57. ↑ Curtis CD, Likhite VS, McLeod IX, Yates JR, Narulli AM (2007). "Interaction of the Tumor Metastasis Suppressor Nonmetastatic Protein 23 Homologue H1 and Estrogen Receptor {alpha} Alters Estrogen-Responsive Gene Expression". Cancer Res. 67 (21): 10600–7. doi:1158/0008-5472.CAN-07-0055 Check |doi= value (help). PMID 17975005. Unknown parameter |month= ignored (help)
  58. ↑ Klouckova I, Hrncirova P, Mechref Y, Arnold RJ, Li TK, McBride WJ, Novotny MV (2006). "Changes in liver protein abundance in inbred alcohol-preferring rats due to chronic alcohol exposure, as measured through a proteomics approach". Proteomics. 6 (10): 3060–74. doi:0.1002/pmic.200500725 Check |doi= value (help). PMID 16619309. Unknown parameter |month= ignored (help)
  59. ↑ "GENATLAS : GENE Database GLUL".
  60. ↑ "Apropos IpiRecord: IPI00830929".
  61. ↑ Campbell, Neil A. (1987). Biology. p. 795. ISBN 0-8053-1840-2.
  62. ↑ Ellis RJ (2001). "Macromolecular crowding: obvious but underappreciated". Trends Biochem. Sci. 26 (10): 597–604. doi:10.1016/S0968-0004(01)01938-7. PMID 11590012. Unknown parameter |month= ignored (help)
  63. ↑ Zhou HX, Rivas G, Minton AP (2008). "Macromolecular crowding and confinement: biochemical, biophysical, and potential physiological consequences". Annu Rev Biophys. 37: 375–97. doi:10.1146/annurev.biophys.37.032807.125817. PMID 18573087.
  64. ↑ "Nuclear Protein Database: DNA-directed RNA polymerase II largest subunit".
  65. ↑ Nieva C, Gwoźdź T, Dutko-Gwoźdź J, Wiedenmann J, Spindler-Barth M, Wieczorek E, Dobrucki J, Duś D, Henrich V, Ożyhar A, Spindler KD (2005). "Ultraspiracle promotes the nuclear localization of ecdysteroid receptor in mammalian cells". Biol Chem. 386 (5): 463–70. doi:10.1515/BC.2005.055.
  66. ↑ 66.0 66.1 66.2 66.3 66.4 66.5 66.6 Huang SM, Huang SP, Wang SL, Liu PY (2007). "Importin α1 is involved in the nuclear localization of Zac1 and the induction of p21WAF1/CIP1 by Zac1". Biochem J. 402 (Pt 2): 359–66. doi:10.1042/BJ20061295. PMID 17109628. Unknown parameter |month= ignored (help)
  67. ↑ "Entrez Gene: RANGRF RAN guanine nucleotide release factor".
  68. ↑ "Entrez Gene: DISC2 disrupted in schizophrenia 2 (non-protein coding)".
  69. ↑ "Nuclear Protein Database: Rnase P 30kD".
  70. ↑ "Nuclear Protein Database: RPP25".
  71. ↑ 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.
  72. ↑ 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". J of Cell Biol. The Rockefeller University Press. 135: 1195–1205. doi:10.1083/jcb.135.5.1195. PMID 8947544.
  73. ↑ Lohe, A.R.; et al. (1993). "Mapping simple repeated DNA sequences in heterochromatin of Drosophila melanogaster". Genetics. 134 (4): 1149–1174. ISSN 0016-6731. PMID 8375654.
  74. ↑ Lu, B.Y.; et al. (2000). "Heterochromatin protein 1 is required for the normal expression of two heterochromatin genes in Drosophila". Genetics. 155 (2): 699–708. ISSN 0016-6731. PMID 10835392.
  75. ↑ 75.0 75.1 Abney JR, Cutler B, Fillbach ML, Axelrod D, Scalettar BA (1997). "Chromatin Dynamics in Interphase Nuclei and Its Implications for Nuclear Structure". J Cell Biol. 137 (7): 1459–68. PMID 2137814. Unknown parameter |month= ignored (help)
  76. ↑ 76.0 76.1 76.2 76.3 Eskiw CH, Dellaire G, Mymryk JS, Bazett-Jones DP (2003). "Size, position and dynamic behavior of PML nuclear bodies following cell stress as a paradigm for supramolecular trafficking and assembly". J Cell Sci. 116 (Pt 21): 4455–66. doi:10.1242/jcs.00758. PMID 13130097. Unknown parameter |month= ignored (help)
  77. ↑ Schwarzacher HG, Wachtler F (1993). "The nucleolus". Anat Embryol (Berl). 188 (6): 515–36. PMID 8129175. Unknown parameter |month= ignored (help)
  78. ↑ Coggeshall RE, Chung K, Bee DE (1985). "The relation of nucleolus diameter to cell body diameter in mammalian dorsal root ganglion cells". Anat Rec. 211 (2): 213–7. PMID 3977089. Unknown parameter |month= ignored (help)
  79. ↑ 79.0 79.1 Blumenstein R, Amenta PS (1981). "An interferometric analysis of nucleoli in cultured mesothelial cells". Anat Rec. 201 (1): 13–21. doi:10.1002/ar.1092010103. PMID 7030143. Unknown parameter |month= ignored (help)
  80. ↑ Nickerson J (2001). "Experimental observations of a nuclear matrix". J. Cell. Sci. 114 (Pt 3): 463–74. PMID 11171316. Unknown parameter |month= ignored (help)
  81. ↑ Tetko IV, Haberer G, Rudd S, Meyers B, Mewes HW, Mayer KF (2006). "Spatiotemporal expression control correlates with intragenic scaffold matrix attachment regions (S/MARs) in Arabidopsis thaliana". PLoS Comput. Biol. 2 (3): e21. doi:10.1371/journal.pcbi.0020021. PMC 1420657. PMID 16604187. Unknown parameter |month= ignored (help)
  82. ↑ Dundr M, Misteli T (2001). "Functional architecture in the cell nucleus". Biochem J. (356): 297–310. doi:10.1146/annurev.cellbio.20.010403.103738. PMID 11368755.
  83. ↑ Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, Peter Walter, ed. (2002). Molecular Biology of the Cell, Chapter 4, pages 191-234 (4th ed.). Garland Science.
  84. ↑ Misteli T (2001). "Protein dynamics: implications for nuclear architecture and gene expression". Science. 291 (5505): 843–7. PMID 11225636. Unknown parameter |month= ignored (help)
  85. ↑ 85.0 85.1 "GENATLAS : GENE Database MYO1F".
  86. ↑ 86.0 86.1 Platani M, Goldberg I, Swedlow JR, Lamond AI (2000). "In Vivo Analysis of Cajal Body Movement, Separation, and Joining in Live Human Cells". J Cell Biol. 151 (7): 1561–74. doi:10.1083/jcb.151.7.1561. PMID 11134083. Unknown parameter |month= ignored (help)
  87. ↑ Scherthan H, Orr-Weaver T, Arana P, Gill B (1997). Henriques-Gil N, Parker JS, Puertas MJ, ed. Meiotic mobility and recombination. 12. Springer. p. 225. ISBN 0412752409, 9780412752407 Check |isbn= value: invalid character (help). Unknown parameter |proceedings title= ignored (help); More than one of |pages= and |page= specified (help)
  88. ↑ 88.0 88.1 Smetana K, Jirásková I, Otevrelová P, Kalousek I (2008). "The RNA content of nucleolar bodies is related to their size - a cytochemical study on human monocytes and lymphocytes in blood smears and blood cytospins". Folia Biol (Praha). 54 (4): 130–3. PMID 18808739.
  89. ↑ Horký M, Kotala V, Anton M, Wesierska-Gadek J (2002). "Nucleolus and apoptosis". Ann N Y Acad Sci. 973: 258–64. PMID 12485873. Unknown parameter |month= ignored (help)


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