Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Our present data indicate that the Mr 34-40,000 polypeptides which are involved in the binding of a large fraction of hnRNA sequences, including mRNA, are for the most part metabolically stable species in mouse ascites tumor cells. An exception to this generalization is the smallest of 30S RNP core polypeptides, the Mr 34,000 protein, which has a relatively high turnover rate. The relationship of the various synthesis and degradation rates to the physiological state of mammalian cells remains to be determined, as does the pathway of assembly and disassembly of RNP substructures during re-utilization of the proteins and during their turnover. Immunofluorescent studies, which have confirmed the expected nucleoplasmic or euchromatic localization of the RNP core proteins, have also indicated that these species are stable during mitosis, at which time they are dispersed through the cell away from the condensed chromosomes. The proteins appear to relocate in the nucleus as soon as the nuclear envelope is reformed.
Mol Biol Rep 1979 May 31
PMID:HnRNP core proteins: synthesis, turnover and intracellular distribution. 11 Oct 32

Analysis of the temperature dependence of fluorescence polarization of ethidium bromide adsorbed on the double helical fragments of 16S RNA's hairpin loops was used to characterize the intramolecular flexibility of RNA in the free state and within 30S subunit. We show that the local mobility of RNA segments is strongly limited by the tertiary structure of 16S RNA and ribosomal proteins reinforce these limitations. It was suggested that the mechanism of the temperature dependent RI particle activation involved the temporary increase of the local mobility of RNA segments in RNP which favored the formation of the new intraribosomal contacts. A comparison of sw 20 dependences of RNA and 30S subunit on Mg+ and K+ concentrations leads to the proposal that RNA in the small subunit in the physiological conditions has the stressed conformation. This conformation is maintained by the Mg2+-dependent RNA-RNA interactions induced by ribosomal proteins and specific only for the subunit.
Mol Biol (Mosk)
PMID:[Compact structure of the small E. coli ribosomal subunit and its RNA studied by fluorescence spectroscopy and sedimentation analysis]. 37 4

Nuclear 30S RNP particles were studied by means of fluorescence techniques. It's shown that fluorescamin interacts with NH2-groups of protein molecule. As a result, covalent fluorescent label is formed. Quantum yield (rho), fluorescence spectra, lifetime of excited state (tau) and polarization of fluorescamin complexes with 30S particles were studied. Excitation spectra have their maximum at 395 nm, and fluorescence spectrum at 480 nm. These figures correspond to spectra of fluorescamin complexes with NH2-groups of lysine. Mean quantum yield (rho = 0.27) and lifetime of excited state of fluorescence (tau = 7.8 nsec) were measured. It's shown that fluorescamin forms two types of fluorescent complexes in 30S particles. These complexes differ only by their rho(rho1 = 0.11, rho2 = 0.30) and rho(rho1 = 3.6 nsec, rho2 = 10.0 nsec) by 2.7 times. Migration radius between fluorescamin bound to protein and ethydium bromide adsorbed on double-stranded regions of pre-mRNA in RNP-particles was measured. It's equal to 32 A. Adsorbtion isotherms of ethydium bromide were measured by fluorescence in 0.1 and 0.4 M NaCl. Data obtained showed that 6% of pre-mRNA in 30S particles bound the dye as a strong complex, i. e. this part of pre-mRNA is double-stranded. RNase treatment of RNP had no effect on this value. But the increase of NaCl concentration up to 0.4 M caused the dissociation of protein subunits to some extent followed by appearance of up to 40% free NH2-groups interacting with fluorescamin. Measuring of energy migration from fluorescamin to ethydium bromide showed that double-stranded pre-mRNA regions strictly bound to protein sticked out from RNP particle at a distance of about 27 A. The increase of NaCl concentration up to 0.4 M leads to disruption of this strict bond of double-stranded regions with protein. As a result, these regions of pre-mRNA become labile and move away from the RNP particle at more than 30 A. According to theoretical calculations, there is about 1--2 pre-mRNA hairpins (18--9 base pairs respectively) per one 30S particle.
Mol Biol (Mosk)
PMID:[Nuclear ribonucleoproteins containing pro-mRNA. XIV. Structural study using ethidium and fluorescamine]. 44 Mar 9

Conditions for the isolation of intact poly(A)+mRNP from cryptobiotic gastruale of A. salina are described. In the presence of Mg2+ ions nucleolytic cleavage occurs in vitro in the vicinity of the 3'-poly(A) segment of mRNP during the isolation procedure. The resulting two parts of poly(A)+mRNP complex are separated by thermal elution from oligo(dT)-cellulsoe affinity column. Analysis by SDS-gel electrophoresis of protein components associated with intact poly(A)+mRNP has revealed the existence of 20--30 S RNP complex containing five major proteins with Mr 68,000, 53,000, 50,000, 45,000 and 38,000, respectively, but completely lacking the poly(A)-specific Mr 76,000 protein.
Mol Biol Rep 1979 May 31
PMID:Characterization of protein components of poly(A)-containing messenger ribonucleoproteins from cryptobiotic gastrulae of Artemia salina. 46 Jan 83

Two discreet in size molecular classes of metabolically stable messenger-like RNA molecules with sedimentation coefficientes about 28S and 18S have been revealed in the nuclei of pigeon bone marrow cells. The structural pecularities of 28S RNA class were investigated more carefully. It was shown to constitute the largest fraction of nuclear messenger-like RNA and is characterized by a GC/AU ratio 1.13. As pulse-labeled nuclear RNA, 28S stable nuclear RNA hybridizes with the unique and rare repeated DNA, it does not contain poly(A)-sequences and is found in a form of RNP particles with density of 1.41 g/sm3, tightly bound to chromatin.
Mol Biol (Mosk)
PMID:[Metabolically stable classes of nuclear messenger-like RNA. I. Detection and molecular characterization]. 46 Jan 88

Some characteristic peculiarities of the 5'-end and 3'-end structures of pre-mRNA isolated from nuclear RNP particles have been investigated: presence of triphosphorylated nucleotides on the 5'-ends, as a characteristic of the primary product of transcription; presence of modified 5'-ends -- blocked and methylated structures -- caps; presence of poly(A) blocks attached to the 3'-end of pre-mRNA during post-transcriptional transformation of the latter. It was shown that pre-mRNA isolated from nuclear RNP particles contained triphosphorylated nucleotides as well as a "cap" structure at the 5'-ends. On the 3'-ends of pre-mRNA from nuclear RNP particles isolated in the presence of a RNAse inhibitor, the presence of poly(A) blocks have been shown. These poly(A) structures are separated very easily from pre-mRNA during mild RNAase digestion. This is the reason why they are not detected in 30S monoparticles, containing pre-mRNA fragments connected with one informofer. Almost all poly(A) complexes in this condition are combined with proteins and have the sedimentation coefficient of about 14S. It was concluded that formation of nuclear pre-mRNA containing RNP-particles take place just after the onset of RNA synthesis. All processing steps occur with pre-mRNA packed in nuclear RNP particles.
Mol Biol (Mosk)
PMID:[Nuclear RNP, containing pre-mRNA. XIV. Nature of particles, containing 5'- and 3'-end structures]. 46 Jan 91

Large amounts of RNA and RNP isolated from influenza virus were obtained. This has allowed us to undertake detailed physical studies of the secondary structure of RNA of influenza virus in free form and in RNP. Analysis of CD spectrum and the hypochromic effect after thermal denaturation of RNA indicated that RNA in free form contains 58--62% double-stranded regions. By comparative studies of the secondary structure of RNA in RNP, it was estimated that 12--14% of the RNA exists in double-stranded form.
Mol Biol (Mosk)
PMID:[Secondary structure of RNA of influenza virus in free form and in ribonucleoprotein]. 46 Feb 7

The state of hepatocyte chromatin (the area occupied by the regions of condensed chromatin on ultrathin sections and the quantity of perichromatin RNP fibrils which was estimated by the area of the fibrillar zone and the concentration of fibrils within the same zone) were studied within the first hours after partial hepatectomy of guinea pigs. The area occupied by the regions of condensed chromatin on preparations with differentially revealed DNP and RNP components decreased by 12% in 2.5 hours since the operation had been performed, became normal in 5 hours, and again decreased by 30% in 9 hours. Decondensation of chromatin was accompanied with the increase of the number of perichromatin RNP fibrils, products of template activity of chromatin, and the rise of ethidium bromide binding. The binding of ethidium bromide by the chromatin of hepatocytes increased by 39% in 2.5 hours, returned to the control level in 5 hours and again increased by 22% in 9 hours.
Mol Biol (Mosk)
PMID:[Electron microscope examination of chromatin in hepatocyte nuclei within the first hourse after partial hepatectomy, II. The degree of chromatin condensation and the organization of fibrillar RNP components]. 54 78

The 30S nuclear RNP particles from rat liver have been shown to split the double-stranded- (ds) and single-stranded (ss) sequences of nuclear pre-mRNA. Experiments performed in vitro have demonstrated that 1) a 5'-exonuclease and an endonuclease specific for double-stranded pre-mRNA sequences exist in the 30S pre-mRNP particles; 2) in dsRNA monophosphorylated 5'-termini arose in the course of incubation with 30S RNP and most of the products remained double-stranded. The analysis of terminal pNp nucleotides revealed a relatively high ratio of pPyp in the cleaved dsRNA, whereas the nucleosides in 5'-terminal pNp of ssRNA showed nearly random distribution. Our results provide a possible explanation for the appearance of pNp termini during the processing of nuclear pre-mRNA of mammalian cells.
Mol Biol Rep 1978 Oct 16
PMID:Cleavage of pre-mRNA sequences by ribonucleases bound to nuclear RNP particles of rat liver. 73 82

Two proteins were isolated from preparations of weakly bound nonhistone proteins, obtained from highly purified chromatin with 0.35 M NaCl. These two protein residues from chromatin RNP-particles have the buoyant density of 1.41 g/cm3 as shown by centrifugation in CsCl gradients and contain heterogeneous fast labelling nuclear RNA. According to SDS polyacrylamide gel electrophoresis the molecular weights of these proteins are 70000 and 43000 daltons.
Mol Biol (Mosk)
PMID:[Nonribosomal ribonucleoprotein particles in preparations of nonhistone proteins extracted from pigeon erythroblast chromatin]. 73 90


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