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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A comparative study was made of the specificity and some properties of the RNase and DNase activities of exonuclease A5. The results obtained indicate that RNA and denatured DNA are hydrolyzed in the same active center of the enzyme and, consequently, exonuclease A5 is an enzyme which is not specific for the sugar of nucleic acids. The data reported are important when exonuclease A5 is used as a specific reagent in investigations of nucleic acids.
Mol Biol (Mosk)
PMID:Ribonuclease and deoxyribonuclease activity of exonuclease A5. 1 11

Ribonucleic acid extracts of lymphoid cells from immune hosts were used to transfer in vivo and in vitro cell-mediated immune reactivity to a variety of antigens. The in vivo immune responses transferred by RNA included the delayed cutaneous hypersensitivity reaction to fungal and chemically-defined antigens and the tumor-rejection reaction to guinea pig hepatoma antigens. The in vitro immune responses transferred by RNA included macrophage migration inhibition by fungal, chemically-defined, and tumor antigens. The transfer activity of RNA preparations was contained in the 8 s to 18 s species of RNA and was sensitive to RNase but not to DNase or trypsin. Antigen was not detectable in the RNA preparations and appeared to have no role in the transfer activity. Syngeneic, allogeneic, or xenogeneic sources of RNA could transfer immune reactivity. In each system tested, the transfer of cell-mediated reactivity by RNA was specific for the antigen used to sensitize the RNA donor. The potential use of RNA-mediated transfer of immunity is discussed.
Mol Cell Biochem 1979 May 06
PMID:Some perspectives on the transfer of cell-mediated immunity by immune-RNA. 11 79

Nuclear ribonucleoprotein (RNP) complexes that contain the U1 and U2 RNA of chromatin of Novikoff hepatoma cells were extracted with 0.01 M Tris-HCl (pH 8.0) after the nuclei were initially washed with 0.075 M NaCl and 0.025 M EDTA (pH 8.0). These RNP complexes were purified by chromatography on Sepharose 6B columns and centrifugation on sucrose density gradients. The identity of the U1 and U2 RNA in these particles was established by their electrophoretic mobility in polyacrylamide gels and their T1 RNase fingerprints which were identical with those of authentic U1 and U2 RNA (R. Reddy et al. (1974), J. Biol. Chem.249, 6486-6494; H. Shibata et al. (1974), Mol. Cell. Biochem. 4, 3-19). The nuclear riboncleoproteins had a buoyant density of 1.47 g/ml in CsCl gradients. Two-dimensional polyacrylamide gel electrophoresis of their proteins showed these RNP complexes contain 10 polypeptide spots, of which two are phosphorylated in vivo.
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PMID:Nuclear ribonucleoprotein complexes containing U1 and U2 RNA. 16 94

The action of ribonucleases on poly and oligoribonucleotides containing cytosine bases modified by methoxyamine and bisulphite was examined. Resistance of phosphodiester bonds in (Cp)nXp (where n greater than or equal to 1 and X stands for A, G or U) to T2 RNase hydrolysis was observed if substrates were modified chemically. The phenomenon formed the basis for isolation of (Cp)nXp blocks as an additional tool in sequence investigations. After modification of cytosine pancreatic RNase was unable to hydrolyse (Cp)nUp blocks. Therefore the specificity of pyrimidyl RNase may be narrowed to 'uridyl RNase'.
Mol Biol Rep 1975 Oct
PMID:A directed alteration of ribonuclease specificity. Hydrolysis of polyribonucleotides containing modified cytosine bases. 17 81

The binding characteristics of [125I]-labeled L-triiodothyronine (T3) to chromatin isolated from rat liver nuclei were investigated. Binding of T3 to chromatin showed temperature-, incubation time-, and DNA concentration-dependence. According to Scatchard analysis, the apparent equilibrium dissociation constant was 225 pM, with a maximum binding capacity of about 0.2 pmoles per mg DNA. Displacement studies with unlabeled thyroxine (T4) and T3 showed that the binding sites for T4 might be the same as T3 but the binding affinity of the former was less than that of the latter. The binding was completely inhibited by the eukaryotic RNA polymerase inhibitor, rifampicin AF/021, but not by the prokaryotic inhibitor, rifampicin and alpha-amanitin. These observations indicate that the receptors for T3 have certain properties in common with RNA polymerase or other enzyme proteins which are sensitive to the rifampicin derivative. The hormone--chromatin fragments complex was solubilized from residual chromatin by digestion with DNase, but not with RNase, suggesting that the T3 receptors localize in the DNase-sensitive regions of DNA in the chromatin. This provides a useful method to use to investigate the localization of the receptor proteins in the chromatin and the interaction of the hormone-receptor complex with DNA.
Mol Cell Endocrinol 1977 Mar
PMID:Binding characteristics of L-triiodothyronine to isolated rat liver chromatin. 19 15

By equilibrium ultracentrifugation and electrophoresis in agarose gel data were obtained on the binding of [3H]cyclic adenosine monophosphate ([3H]cAMP) to the transcriptional complex of mitochondria with the density 1.825 g/ml in CsCl ethydium bromide. Treatment of the complex with RNase, DNase and pronase change the density of [3H]cAMP bound material; rifampicin prevents detection of [3H]cAMP. Study of inner membrane lysates showed that [3H]cAMP is bound to structures active in RNA and protein synthesis in mitochondria. The conclusion is made that cAMP is involved in formation of the transcriptional complex much as it is involved in initiation of transcription in bacterial operons.
Mol Cell Biochem 1977 Feb 04
PMID:Detection of [3H]cyclic AMP in the transcription complex of rat liver mitochondria. 19 94

The RNase hydrolysis of random-coil (alkaline form) poly A follows biphasic kinetics at low salt concentrations. However, its resistance to RNase increases with the ionic strength. Helical (acidic form) poly A is alos susceptible to RNase but its hydrolysis follows first-order kinetics, and its resistance increases as the pH is lowered. These conformation-dependent kinetics of poly A hydrolysis are similar to those obtained in the hydrolysis of cellular RNA and reovirus double-stranded RNA.
Mol Cell Biochem 1975 Oct 31
PMID:The kinetics of pancreatic ribonuclease reaction with alkaline and acidic forms of poly A. 24 30

The presence of RNA-linked nascent DNA pieces in T7 phage-infected Escherichia coli cells has been shown by the selective degradation of the 5'-hydroxyl-terminated nascent DNA, produced by alkali or RNase treatment, with spleen exonuclease. At 43 degrees C, the proportion of RNA-linked DNA pieces in nascent short dna is 50 to 60% in T7 ts136 (ts mutant of gene 6) phage-infected E. coli, whereas that in T7 wild-type phage-infected cells is less than 6%. Joining of the nascent pieces is greatly retarded in T7 ts136-infected E. coli temperature sensitive polA mutants at 43 degrees C. These results suggest that gene 6 exonuclease plays a role in removal of the linked RNA during the discontinuous replication of T7 DNA.
Mol Gen Genet 1977 Sep 09
PMID:RNA-linked nascent DNA pieces in T7 phage-infected Escherichia coli cells. I. Role of gene 6 exonuclease in removal of the linked RNA. 33 6

When cells of Escherichia coli are labeled with 32Pi for long periods of time and the cell content is subjected to electrophoresis in polyacrylamide gels, an RNA band appears which is about 10S in size. This band seems to contain three conformers. After treatment with formamide only a single band appears in this region of the gel, which contains 550 nucleotides as determined from its mobility. The complexity of the fingerprint of this material, after digestion with T1-RNase, is in agreement with the size as determined by the mobility, this confirming that indeed it is a single molecule. Composition of the T1-oligonucleotides was determined by digesting the T1-generated oligonucleotides with pancreatic RNase and T2-RNase. The quantitative and qualitative analysis of these digestions suggest that 10S RNA contains 609 nucleotides. The molecule contains, besides the four regular bases, one copy per molecule of the modified base pseudouridine. 10S RNA cannot be processed by cell extracts to tRNA-sized molecules and does not bind significantly to ribosomes, hence it is unlikely to be a tRNA precursor or an mRNA.
Mol Gen Genet 1979 Jul 02
PMID:Characterization of 10S RNA: a new stable rna molecule from Escherichia coli. 38 59

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


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