Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Poly(1-vinyluracil) and poly(9-vinyladenine), as well as the corresponding polynucleotides poly(uridylate) and poly(adenylate), inhibit acute murine leukemia virus infection in mouse-embryo cells, but they do not significantly inhibit the replication of Sindbis and vesicular stomatitis viruses. The polymers were most effective as inhibitors when added during an early stage of virus replication. Effects of vinyl polymers on the RNA-dependent DNA polymerase from the virions of murine leukemia virus were also observed.
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PMID:Inhibition of murine leukemia virus replication by poly(vinyluracil) and poly(vinyladenine). 412 32

Single-stranded polyribonucleotides, which competitively inhibit murine RNA tumor virus reverse transcriptase in vitro, were tested as inhibitors of various virus functions in cell culture. The compounds had two concentration-dependent effects. At high concentrations (100 mug/ml), both poly(adenylic acid) [poly(A)] and poly(2'-O-methyladenylic acid) [poly(Am)] inhibited the uptake of radioactively labeled leukemia virus by Swiss mouse embryo cells, but neither had a similar effect on Sindbis virus adsorption. At low concentrations (10 mug/ml), poly(Am) did not inhibit the uptake of leukemia virus but did inhibit virus replication by 85%; in contrast, the replication of Sendai virus and Sindbis virus was not inhibited significantly at this concentration. Both compounds were effective only when added prior to or early during virus infection. Poly(Am) was a much more effective inhibitor than poly(A), probably due to the nuclease resistance of the former compound. Poly(Am) at 5 mug/ml also inhibited transformation of 3T3 cells by Moloney sarcoma virus. However, neither poly(A) nor poly(Am) at high concentrations inhibited the activation of endogenous leukemia virus by iododeoxyuridine in AKR mouse embryo cells. These results suggest that virus reverse transcriptase plays an essential role in both the replication of exogenous murine leukemia viruses and the transformation of cells by murine sarcoma viruses but probably has no role in the activation of endogenous leukemia virus.
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PMID:Effects of polyadenylic acids on functions of murine RNA tumor viruses. 412 77

Poly(A)-containing RNA was isolated from ovaries of Xenopus laevis laevis and Triturus cristatus carnifex and used as a template for the synthesis of radioactive complementary DNA with RNA-dependent DNA polymerase. When annealed with an excess of homologous DNA, the complementary DNA is rendered double-stranded with kinetics that suggest that the coding sequences are single-copy in both these organisms. In Triturus, these sequences are distinct from the majority of the genome, which consists of repeated sequences, and distinct from the ribosomal cistrons, which are present in proportion to the increase in C-value relative to the Xenopus genome. Moreover, the number of different poly(A)-containing molecules in the ovary (sequence complexity) is the same in Xenopus and in Triturus.
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PMID:Analysis of the C-value paradox by molecular hybridization. 413 20

Free polysomes were isolated from the livers of rats maintained on a 60% casein diet to induce ornithine aminotransferase mRNA. Ornithine aminotransferase-synthesizing polysomes were immunoadsorbed using monospecific, affinity-purified antibody and Staphylococcus aureus cells. Poly(A+)RNA prepared from these polysomes by oligo(dT)-cellulose chromatography was used as a template for the synthesis of double-stranded cDNA by reverse transcriptase. Using the deoxyguanosine-5'-triphosphate-deoxycytidine-5'-triphosphate tailing method and pBR322 as a vector, recombinant molecules were produced and used to transform Escherichia coli. Two clones containing DNA complementary to ornithine aminotransferase mRNA were identified by colony hybridization and hybrid-arrest translation. A partial restriction endonuclease map of the ornithine aminotransferase cDNA inserts was constructed which spanned 1066 base pairs.
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PMID:Cloning of DNA complementary to ornithine aminotransferase mRNA. 612 4

Poly(A+)--RNA from rat ventral prostate was isolated using oligo(dT)-cellulose chromatography. 45% of the total poly(A+)--RNA was a single peak at 10S as demonstrated by centrifugation in a 5-20% sucrose gradient containing 1% SDS. By using complementary DNA probes, it was shown that the 10S RNA contained the major abundance class of poly(A+)--RNA. Denaturing agarose-gel analysis revealed 2 major bands in the 10S poly(A+)--RNA preparation approx. 600 NT and 500 NT (NT = nucleotides) long, resp. Double-stranded 32 P-DNAs complementary to light side and heavy side of the 10S poly(A+)--RNA peak were synthesized and isolated using reverse transcriptase and hydroxyapatite (HAP) chromatography. Approx. 40% of the first strand of the cDNAs were converted to double-stranded structures with a Tm of 88 degrees C. HAP purified double-stranded material was 92% resistant to S1 nuclease. the DNA--DNA reannealing profile of double stranded 32 P-cDNA enriched for the 500 NT band gave a Cot 1/2 of approximately 7 X 10(-4) moles X sec X 1(-1) indicating a complexity for this enriched synthetic gene of 500-600 nucleotide pairs (NTP).
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PMID:Purification of major abundance class of poly(A+)-RNA from rat ventral prostate. 615 88

Polyinosinic acids containing methyl and sulphur substitutions are potent inhibitors of reverse transcriptase. Substitution of sulphur for oxygen at the 6 position produces significant effects on the properties of polyinosinic acid: the kinetics of inhibition change from competitive to mixed-type and the inhibition constant falls by three orders of magnitude. In contrast, 1-methyl substitution produces no such effects. Poly(1-methyl-6-thioinosinic acid) or poly(m1s6I) inhibits irreversibly, inhibiting all ten reverse transcriptases tested under a variety of assay conditions. In cell culture test systems, poly(m1s6I) is capable of blocking both infection by non-transforming viruses and transformation by a sarcoma virus. The presence of poly(m1s6I) in a preinfected culture results in the production of non-infectious virus particles lacking reverse transcriptase activity.
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PMID:Antiviral properties of polyinosinic acids containing thio and methyl substitutions. 616 84

Poly(A)-containing RNA was isolated from total RNA of swine gastric mucosa by oligo(dT)-cellulose chromatography, and was translated in a wheat germ cell-free system. Analysis of the translation products by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that pepsinogen was a major translation product and was synthesized as two different molecular forms with apparent molecular weights of 45,000 and 43,000. The pepsinogen translated in the in vitro translation system had no autocatalytic activity. The pepsinogen mRNA was further purified by sucrose density gradient centrifugation, where the mRNA activity for pepsinogen was located around 15 S. At this stage, the translation product of the pooled fractions appeared to be almost exclusively pepsinogen. The peptide maps of the pepsinogen which was translated in vitro and digested by alpha-chymotrypsin and by Staphylococcus aureus V8 protease were nearly identical with the corresponding peptide maps of standard pepsinogen. The double-stranded complementary DNA which had been synthesized from the partially purified mRNA by avian myeloblastosis virus reverse transcriptase was cloned in Escherichia coli chi 1776, using plasmid pBR322 as a cloning vector. A colony carrying pepsinogen cDNA sequence was identified by in situ colony hybridization using the cDNA synthesized from the partially purified mRNA as a probe and further by a positive hybridization-translation assay. One of the recombinant clones (pSPcA1) had an insert of about 850 base pairs, and the nucleotide sequence analysis revealed that pSPcA1 codes for swine pepsinogen.
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PMID:Molecular cloning of complementary DNA to swine pepsinogen mRNA. 617 Jun 44

We had shown earlier (Gopalakrishna, Y., Langley, D., Sarkar, N. (1981) Nucleic Acid Res. 9, 3545-3554) that a substantial fraction of mRNA of various bacterial species carries 3'-terminal polyadenylate sequences. In this paper, we show that poly(A)-containing RNA from Bacillus subtilis can serve as template for the synthesis of complementary DNA by avian myeloblastosis virus reverse transcriptase, provided that oligodeoxythymidylate is added as primer. Poly(A)-RNA purified by affinity chromatography on oligo(dT)-cellulose was 20 times more effective as template for cDNA formation than total bacterial RNA, whereas rRNA was inactive. The average chain length of the cDNA was 400 nucleotides (range = 230-800 nucleotides), and 95% of the cDNA could be degraded by the single-strand specific S1 nuclease after denaturation. The small fraction (5%) that was resistant to S1 nuclease may represent duplex hairpin structures. Annealing with poly(A)-RNA protected cDNA from degradation by S1 nuclease, indicating that cDNA indeed contains nucleotide sequences complementary to poly(A)-RNA. These results constitute independent evidence that a large fraction (about 40%) of B. subtilis mRNA is polyadenylated. Moreover, the synthesis of cDNA to bacterial mRNA provides an important new tool for the study of bacterial mRNA structure.
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PMID:The synthesis of DNA complementary to polyadenylate-containing RNA from Bacillus subtilis. 617 11

The effects of partially thiolated polyuridylic acid (MPU), partially thiolated polycytidylic acid (MPC), and their unmodified counterparts, poly(U) and poly(C), respectively, on the reverse transcriptase of avian myeloblastosis is virus (AMV) have been determined, using different template-primers. Poly(C) stimulated and MPC inhibited the polymerization reaction catalyzed by the AMV reverse transcriptase in the presence of the natural viral template (endogenous RNA or purified 70S RNA), or with poly(C) . oligo(dG)12-18 but not with poly(A) . oligo(dT)12-18 as the only template-primer present in the purified enzyme system. Both poly(U) and MPU inhibited the reaction in the presence of either of the synthetic or natural templates. Using the purified enzyme with the 70S RNA template, MPU was by far the most potent inhibitor, with I50 = 0.8 microM based on the epsilon (P) value, or I50 less than 3 x 10(-9) M based on the actual, macromolecular weight of the polynucleotide.
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PMID:5-Mercaptopolyuridylic acid (MPU), a potent inhibitor of the reverse transcriptase from avian myeloblastosis virus. 617 37

Terminal deoxynucleotidyl transferase (TdT) was used to prepare copolymers of dA and 1,N6-ethenodeoxyadenosine (epsilon dA). When used as templates for Escherichia coli DNA polymerase I (Pol I) and compared with poly (dA), normal dTTP incorporation was not significantly affected by the presence of 7% epsilon dA. dGTP misincorporation was only slightly increased and occurred about once for every 500 epsilon dA residues. The error-prone polymerase from avian myeloblastosis virus (AMV reverse transcriptase) increased this error rate 5- to 20-fold to a maximum of 1 dG/25 epsilon dA. No dCTP misincorporation was detected with either polymerase. In transcription with E. coli DNA-dependent RNA polymerase, no errors were revealed by nearest neighbor analysis. Poly (dA) treated with chloroacetaldehyde under conditions producing the same proportion of epsilon dA (without the hydrated form) as the synthesized template behaved in the same manner with a similar low level of misincorporation of dG. Such treatment of alternating poly d(A-T) caused structural changes indicative of crosslinks but did not alter its template properties. Increasing the amount of epsilon dA in either synthesized or modified polymers greatly decreased the template activity without increasing the error rate. It is suggested that epsilon dA generally does not prevent dT incorporation but behaves as a bulky lesion which is bypassed. In contrast to the low mutagenic efficiency of epsilon dA, O4-methyldeoxythymidine (m4dT), in copolymers with dA, directed the misincorporation of 1 dG/12 m4dT with Pol I and 1 dG/3 m4dT with reverse transcriptase. Nearest neighbor analysis of transcripts showed the incorporation of 1 dG/12 m4dT. These data are in agreement with the previous reported mutagenicity of m4dT in alternating poly d(A-T, m4T).
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PMID:Assessment of mutagenic efficiency of two carcinogen-modified nucleosides, 1,N6-ethenodeoxyadenosine and O4-methyldeoxythymidine, using polymerases of varying fidelity. 620 83


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