Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.1 (RNase)
 16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Reticuloendotheliosis viruses (REV) contain an endogenous RNA-directed DNA polymerase activity. The endogenous DNA polymerase activity can be elicited in purified preparations of REV by treatment with nonionic detergents. The enzyme activity has a strong preference for manganous ions. Therefore, appreciable endogenous DNA polymerase activity can be demonstrated only if the reaction mixture contains appropriate concentrations of manganous ions. Enzyme activity can be inhibited by pretreatment with RNase or deletion of one or more deoxyribonucleoside triphosphates from the reaction mixture. In contrast, actinomycin D has little effect in initial DNA synthesis. The results from both velocity and equilibrium centrifugation indicate that the nascent chains of product DNA are associated with 60S viral RNA. The DNA product of the endogenous DNA polymerase reaction is hybridizable to REV RNA, but not to avian leukosis virus RNA.
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PMID:Characterization of endogenous RNA-directed DNA polymerase activity of reticuloendotheliosis viruses. 5 36

Early chicken embryos that are either positive or negative for group-specific antigens of avian leukosis viruses contained endogenous RNA-directed DNA polymerase activity. This endogenous DNA polymerase activity was not increased after mixture of soluble DNA polymerases isolated from chicken embryos with disrupted chicken embryo cells. The endogenous activity was resistant to treatment with deoxyribonuclease, and the initial rate of DNA synthesis was partially resistant to actinomycin D. In contrast, over 90% of the endogenous polymerase activity was destroyed by ribonuclease in medium with high salt concentration. The DNA product of the endogenous DNA polymerase activity from chicken embryos did not hybridize with RNA of Rous sarcoma virus or reticuloendotheliosis virus, whereas about 40% of this DNA product hybridized with the RNA from the same chicken-cell fraction. Antibody against DNA polymerase of avian myeloblastosis virus did not neutralize the chicken endogenous DNA polymerase activity. These results demonstrate that uninfected chicken embryo cells contain endogenous RNA-directed DNA polymerase activity that is not derived from avian leukosis or reticuloendotheliosis viruses.
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PMID:Endogenous RNA-directed DNA polymerase activity in uninfected chicken embryos. 433 97

Two small RNAs (0.9 and 0.75 kb), named Marek's disease virus (MDV) small RNAs (MSRs) and a 10-kb RNA, all of which map antisense to the MDV ICP4 homolog gene, have been readily detected in MDCC-MSB1 MDV-transformed T-lymphoblastoid cells. These RNAs were not detectable in reticuloendotheliosis virus-transformed T cells. When MDV was reactivated by treatment of lymphoblastoid cells with 25 micrograms of iododeoxyuridine per ml, the relative levels of the transcripts decreased. These RNAs were not detected by Northern (RNA) hybridization in productively infected chicken embryo fibroblasts 48 h postinfection; however, they were apparent 140 h postinfection. By using Northern hybridization, RNase protection assays, and primer extension analysis, the MSRs were determined to map antisense to the predicted translational start site of the ICP4 homolog gene. The conclusion most consistent with the data is that the two MSRs are overlapping, spliced RNAs. Both small RNAs contain a latency promoter binding factor consensus recognition sequence located toward their 5' ends as well as two potential ICP4 recognition consensus sequences, one in each orientation. The region contains a number of small open reading frames on each side and within the MSRs. Although the exact endpoints are unknown, the large 10-kb species spans the entire ICP4 homolog region. We believe that this group of RNAs, which map antisense to the ICP4 homolog gene, are latency-associated transcripts of MDV.
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PMID:Identification of latency-associated transcripts that map antisense to the ICP4 homolog gene of Marek's disease virus. 808 68

Two Marek's disease (MD) virus BamHI-L-specific cDNA clones were isolated from a cDNA library constructed from poly(A)+ RNA fractions of an MD lymphoblastoid cell line, MDCC-CU41 (CU41). These clones were mapped to the region corresponding to the BamHI-Q2 and L-regions. These clones hybridized with 2.5-, 0.8-, and 0.6-kb transcripts prepared from CU41. The transcriptional unit of the 0.6-kb transcript was determined by RNase protection assays. An open reading frame encoding a 107-amino-acid polypeptide was identified in the 0.6-kb transcript. Reverse transcriptase-PCR demonstrated the presence of this transcript in both CU41 and a reticuloendotheliosis virus-transformed cell line latently infected with MD virus.
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PMID:Characterization of a Marek's disease virus BamHI-L-specific cDNA clone obtained from a Marek's disease lymphoblastoid cell line. 828 49