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1.
In vitro association of unique species of cellular 4S RNA with 35S RNA of RNA tumor viruses 总被引:3,自引:0,他引:3
L C Waters B C Mullin T Ho W K Yang 《Biochemical and biophysical research communications》1974,60(2):489-497
Unique 4S RNA species from AKR mouse embryo cells hybridize with AKR murine leukemia virus and avian myeloblastosis virus 35S RNAs . Analyses by reversed-phase column chromatography indicate that the major 4S species that hybridize with the two viral RNAs are probably the same. A 4S RNA species with similar chromatographic properties is a major component of the AKR viral 4S RNA which associates with the viral 70S RNA . 相似文献
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G F Gerard C Gurgo D P Grandgenett M Green 《Biochemical and biophysical research communications》1973,53(1):194-201
Rifampicin and three rifamycin SV derivatives with different lipophilic side chains were tested as inhibitors of a number of purified enzymes including the α and αβ forms of RNA-directed DNA polymerase of avian myeloblastosis virus (AMV). (2,5-dimethyl-4-N-benzyl demethyl rifampicin), (O-n-octyloxime of 3-formyl rifamycin SV) and C-27 (rifamycin SV with a dicyclohexylalkyl substituted piperidyl ring at the 3-position) at concentrations less than 20 to 40 μg/ml completely inhibited the RNA- and DNA-directed DNA polymerase and RNase H activities of both AMV enzymes. Rifampicin was inactive at 100 μg/ml. When used against a variety of non-polymerizing enzymes such as alkaline phosphatase, glutamate-oxaloacetate transaminase, DNase I, and RNase A, these derivatives were inactive at drug concentrations between 100 and 200 μg/ml. Polynucleotide phosphorylase was inhibited slightly by all three derivatives. These results support the idea that rifamycin SV derivatives with appropriate 3-substituted side-chains are specific inhibitors of nucleic acid polymerizing enzymes. 相似文献
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A new endoribonuclease activity, RNase F, was partially purified from cells. This activity can cleave a precursor RNA molecule (of Species 1), isolated from T4 infected cells, in a specific site. This activity is different from the other three know processing endoribonucleases of RNase III, RNase E and RNase P. 相似文献
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P. Ghosh-Dastidar B.B. Goswami A. Das P. Das N.K. Gupta 《Biochemical and biophysical research communications》1981,99(3):946-953
Vaccinia viral core inhibits protein synthesis in reticulocyte lysates. In partial reactions using micrococcal nuclease treated reticulocyte lysates, the viral core inhibits Met-tRNAf binding to 40S ribosomes in response to physiological mRNAs such as globin mRNA, cowpea mosaic viral RNA, and brome mosaic viral RNA but not in response to a trinucleotide codon, AUG. The core has also no effect on Met-tRNAf binding to 40S ribosomes in a partial reaction using partially purified peptide chain initiation factors and AUG codon.The present observation of preferential inhibition by vaccinia viral core of Met-tRNAf·40S initiation complex formation with physiological mRNAs and not with an artificial mRNA such as AUG codon, suggests that the viral core inhibits some step(s) in peptide chain initiation involved in the recognition of structural feature(s) unique to physiological mRNAs. 相似文献
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M J Grubman S A Moyer A K Banerjee E Ehrenfeld 《Biochemical and biophysical research communications》1975,62(3):531-538
Vesicular stomatitis virus (VSV) messenger RNAs (mRNAs) appear to be compartmentalized within the infected HeLa cells. Analysis by polyacrylamide gel electrophoresis in formamide of the RNA associated with the membrane bound polyribosomes from VSV-infected cytoplasmic extracts shows predominantly one size class of VSV mRNA, which is absent from the remaining cytoplasm. These results are consistent with the mRNA for the viral glycoprotein being exclusively associated with membrane bound polysomes since the latter have been shown to synthesize mainly the virion glycoprotein in an translation system. 相似文献
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The broad spectrum antiviral agent ribavirin inhibits capping of mRNA. 总被引:14,自引:0,他引:14
B B Goswami E Borek O K Sharma J Fujitaki R A Smith 《Biochemical and biophysical research communications》1979,89(3):830-836
Ribavirin (1-β-D-ribofuranosyl-1,2,4-triazole-3-carboxamide) is a broad spectrum antiviral substance active against a wide range of both DNA and RNA viruses. It is, however, virtually inactive against polio virus. Its pharmacological mechanism of action was obscure. A possible common target for a chemotherapeutic agent in both DNA and RNA viruses is the “capping” reaction of mRNAs which involves the formation of a guanine pyrophosphate structure at the 5′ terminus by mRNA guanylyl transferase. We have observed that Ribavirin triphosphate is a potent competitive inhibitor of the capping guanylation of viral mRNA. This finding could account for the antiviral potency of the drug against both DNA and RNA viruses and its ineffectiveness against a virus in which the mRNAs derived from them are not capped. 相似文献
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Evidence for the attachment of RNA to pulse-labeled DNA in the slime mold, Physarum polycephalum 总被引:6,自引:0,他引:6
When is pulse-labeled for up to 20 minutes with 3H-thymidine and the shortest labeled DNA strands are partially purified by sedimentation through a neutral aqueous sucrose gradient and then through a formamide-sucrose gradient, these short strands band in Cs2SO4 isopycnic density gradients at a density greater than that of bulk single-stranded DNA. Their density is brought partially or nearly completely back to that of single-stranded DNA by hydrolysis with pancreatic RNase A or alkali, respectively. Therefore the dense material attached to the short pulse-labeled DNA strands consists at least partially of RNA. 相似文献
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Thermal denaturation of nucleocapsids of wild type (WT) vesicular stomatitis virus (VSV), containing only the nucleocapsid protein (N) and viral RNA, caused a “melting” that resulted in an A260nm absorbance increase of 140%. The nucleocapsids of two temperature-sensitive () VSV mutants, G31BP and G22, both underwent larger absorbance increases of 251% and 177% respectively, suggesting these nucleocapsids are complexed by weaker N protein: RNA interactions than the WT-VSV. Two other mutants, G31 and G41 underwent A260nm increases either similar to, or smaller than, that measured with WT-VSV nucleocapsids. RNA synthesis by G31BP in infected cells was also found to be decreased at elevated temperatures. This temperature sensitive defect in viral RNA metabolism in G31BP may be the result of weaker protein:RNA interactions associated with the nucleocapsid. 相似文献
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Stimulation by interferon of induction of differentiation of human promyelocytic leukemia cells 总被引:3,自引:0,他引:3
F1-ATPase was isolated from yeast . The constituent subunits 1 and 2 were purified by gel permeation chromatography, and their amino acid compositions determined. Both subunits have a similar composition except for cystine, methionine, leucine, histidine, and tryptophan. When F1 is treated for three hours with 5′-p-[3H]fluorosulfonylbenzoyl adenosine in dimethylsulfoxide, 90% of the activity is lost. Disc gel electrophoresis of the modified complex showed that over 90% of the label was associated with subunit 2. A labelled peptide from a digest of subunit 2 was isolated and sequenced. It had the following amino acid sequence: His-Try1-Asp-Val-Ala-Ser-Lys-Val-Gln-Glu, whereby Tyr1 is the modified amino acid residue. This sequence shows homology to other sequences obtained from maize, beef heart, and F1-ATPases. 相似文献
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The RNA products synthesized by the virion-associated RNA polymerase of purified vesicular stomatitis virus have previously been shown to contain two distinct 5′-terminal sequences. The mRNA species contain the blocked 5′-terminal G(5′)ppp(5′)A-A-C-A-G sequence and the initiated lead-in RNA segment (approximately 50 bases) contains the unblocked 5′ ppA-C-G sequence. In the present studies, using inosine 5′-triphosphate in place of GTP it is shown that RNA species as large as 14.5S contain an unblocked 5′-ppA-C-(I) sequence indicating that the GTP analogue permits synthesis of a possible precursor of viral mRNA . 相似文献
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Veal heart ribonuclease P has an essential RNA component 总被引:14,自引:0,他引:14
E Akaboshi C Guerrier-Takada S Altman 《Biochemical and biophysical research communications》1980,96(2):831-837
The activity of RNase P (EC 3.1.26.5) from veal heart can be abolished by pretreatment of the enzyme preparation with micrococcal nuclease, pancreatic RNase A, or RNase T1. This indicates that veal heart RNase P contains an RNA component essential for function of the enzyme as has also been shown for RNase P (1–3). Additionally, veal heart RNase P has a buoyant density in Cs2SO4 of 1.33 g/cm3, which is intermediate between that of protein and nucleic acid. 相似文献
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J Germershausen D Goodman E W Somberg 《Biochemical and biophysical research communications》1978,82(3):871-878
RNA (guanine-7) methyltransferase, partially purified from mycelia, catalyzed the transfer of the methyl group from S-adenosylmethionine to the 5′ terminus of both poly A(+) RNA and reovirus unmethylated mRNA. RNase T2 digestion of the methylated poly A(+) RNA from yielded the “cap” structures m 7G(5′)pppAp and m 7G(5′)pppGp in a ratio of 2:1 respectively. RNase T2 digestion of the methylated reovirus mRNA yielded m 7G(5′)pppGp exclusively. The absence of mRNA 2′-0-methyltransferase activity in the enzyme preparation is consistent with the absence of 2′-0-methylation in mRNA [Seidel, B. L. and Somberg, E. W. (1978) Arch. Biochem. Biophys. , 108–112]. This is the first isolation of an eucaryotic, cellular RNA (guanine-7) methyltransferase that has been shown to methylate homologous substrate. 相似文献
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M R Walters W Hunziker A W Norman 《Biochemical and biophysical research communications》1981,98(4):990-996
Previous studies have demonstrated that unoccupied 1,25-dihydroxyvitamin D3 receptors are associated with crude chromatin under hypotonic conditions . The data presented herein show that unoccupied 1,25-dihydroxyvitamin D3 receptors appear to be associated with chromatin prior to solubilization by dilution/homogenization in both high and low salt buffers. Additionally the unoccupied receptors are recovered nearly quantitatively from purified nuclei. These results suggest that unoccupied 1,25-dihydroxyitamin D3 receptors may be localized within nuclei . 相似文献
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Structural alteration of rRNA in the L7/L12 region of 50s ribosome on removal of L7/L12 proteins 总被引:1,自引:0,他引:1
D P ByasmuniBurma 《Biochemical and biophysical research communications》1982,104(1):99-104
Core particles of 50S ribosomes depleted of proteins are degraded by RNase I at a considerably slower rate than intact 50S ribosomes. The normal rate is restored on incorporating proteins into the core particles. The capacity of the core particles to inhibit the RNase I-catalyzed hydrolysis of poly A and to bind ethidium bromide is also greater with core particles than with intact 50S ribosomes. It appears from these results that the region(s) of rRNA in the vicinity of proteins has less ordered structure which, on removal of proteins, becomes more organized. Apparently, binding of proteins to the 50S core leads to the destabilization of double-stranded regions of rRNA. 相似文献
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Hirobumi Teraoka Sanae Tamura Kinji Tsukada 《Biochemical and biophysical research communications》1977,79(1):76-81
Alkaline RNase partially purified from rat liver mitochondria hydrolyzes both RNA and denatured DNA. The behaviors of RNase activity of the nuclease are closely similar to those of the DNase activity. The nuclease has a pH optimum between 9.0 and 9.5, and the activity is absolutely dependent on Mg2+ and reversibly inhibited by -hydroxymercuribenzoate. 相似文献
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The effects of increasing concentrations of sodium deoxycholate on Semliki Forest virus have been studied. Sodium deoxycholate begins to bind to the virus at less than 0.1 mM free equilibrium concentration and causes lysis of the viral membrane at free equilibrium concentration when of sodium deoxycholate are bound per mol of virus. Liberation of proteins from the membrane begins at sodium deoxycholate and the proteins released are virtually free from phospholipid above 2.0 mM sodium deoxycholate. The overall mechanism of sodium deoxycholate solubilization of the viral membrane resembles that of Triton X-100 and sodium dodecyl sulphate except that with sodium deoxycholate the various stages of membrane disruption occur at about 10-fold higher equilibrium free detergent concentrations. At sodium deoxycholate concentrations higher than 2.3 mM the viral spike glycoproteins can be separated by sucrose gradient centrifugation or gel filtration into constituent polypeptides E1, E2 and E3. E1 carries the haemagglutinating activity of the virus. 相似文献
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Keiichi Fukuyama Sherin S. Abdel-Meguid Michael G. Rossmann 《Journal of molecular biology》1981,150(1):33-41
Reassembled alfalfa mosaic virus coat protein was partially digested with trypsin to remove the first 26 amino acids (Bol et al., 1974). These particles are empty icosahedral protein shells built with 60 alfalfa mosaic virus protein subunits. This aggregate has been crystallized in two different crystal forms, one of which diffracts X-rays to at least 3.4 Å resolution. The type I crystals (space group ) contain two particles per cell separated by 195 Å with each sitting on a 3-fold axis. The type II crystals contain three particles per cell in space group P31or P32 (). Other T = 1 viral particles have very similar diameters. 相似文献