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)

Suramin--a well-known antitrypanosomal agent--was found to exert a strong inhibitory effect on the RNA-directed DNA polymerase (reverse transcriptase) activity of several oncornaviruses such as Moloney murine leukemia virus, murine Rauscher leukemia viruses, Moloney murine sarcoma virus and avian myeloblastosis virus. Inhibition of enzyme activity was obtained with both endogenous viral RNA and (A)n . oligo(dT) as the template-primer. Suramin effected a 50% inhibition of the reverse transcriptase activity of oncornaviruses at a concentration range of 0.1--1 microgram/ml. In this aspect it compared favorably to ethidium bromide, another trypanocide drug which is considered as one of the most powerful inhibitors of oncornaviral DNA polymerases. The inhibition of reverse transcriptase activity by suramin was competitive with the template-primer, (A)n . oligo(dT), suggesting that the drug may interact with the template-primer binding site of the enzyme.
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PMID:Suramin: a potent inhibitor of the reverse transcriptase of RNA tumor viruses. 9 62

Relevant data pertaining to present evidence for virus-like particles and virus-related macromolecules in human milk and breast tumors are presented. A critical review and discussion of reported observations concerning virus-related macromolecules will include RNA-directed DNA polymerase, viral antigens, and RNA related to murine mammary tumor virus and/or Mason-Pfizer monkey virus. From the standpoint of clinical applications, the finding of viral-related antigens in human breast tumors and evidence for specific host immune responses to one or more of these antigens may be especially pertinent. The latter data, therefore, will be discussed in depth as to possible employment of these parameters in diagnosis, prognosis and possible management of the human disease.
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PMID:Virus-like particles and macromolecules in human milk and breast tumors. 9 88

Explant cultures from several human prostatic tissues have been examined for oncornavirus production. Some of these explants, epithelial in morphology, appear to release oncornavirus-like particles. The extracellular particulate material, obtained from the culture medium of these explants display the following characteristics: (1) It contains particles that band at a density of 1.1-1.2 g/cm3 in a sucrose density gradient. (2) The particles contain RNA-directed DNA polymerase. This polymerase utilizes poly(Cm) as a template and shows preference for poly(A) over poly(dA) and manganese over magnesium. (3) Apparently, the particles also contain RNA that directs the synthesis of DNA in vitro. The DNA thus synthesized is associated with RNA, some of it with high molecular weight RNA. Such particles are not observed in the culture medium from monolayers of monkey kidney CV-1 cells. We have found that explant cultures from 5 out of 15 tissue specimens with prostatic hyperplasia and 3 out of 4 with prostatic adenocarcinoma release particles that band at a density of 1.1-1.2 g/cm3 and contain RNA-directed DNA polymerase. Explant cultures of two normal prostates examined did not release such particles.
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PMID:Oncornavirus-like particles released by human prostatic explant cultures. 9 78

RNA-directed DNA polymerase was isolated from the liver, spleen, and myeloblasts of chickens that had been infected with virus of avian myeloblastosis. The enzyme was chromatographically purified from the myeloblasts and brought to about 1,000-fold concentration. The method consisted in cell fractionation, lysis of the microsomal fraction, chromatography on Sephadex G-200 and phosphocellulose, as well as ultracentrifugation in the glycerol gradient. The cellular DNA polymerases alpha and beta were clearly separated from the DNA polymerase of avian myeloblastosis virus and could be distinguished from one another by template-specific reactions. The viral DNA polymerase activities in the microsomal fractions of liver, spleen, and myeloblasts were compared with one another. The amount of avian myeloblastosis virus and related DNA polymerase recorded from the myeloblasts was about six times that in the liver and four times higher than that in the spleen. The procedure described, together with the use of cell fractionation and gel filtration, is an appropriate method for biochemical detection of avian oncorna viruses in cells.
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PMID:[Separation of cellular and viral DNA polymerase from oncornavirus infected chicken cells]. 9 56

A human breast tumor cell line BT-474 derived from an invasive ductal carcinoma was experimentally infected in vitro with a mouse mammary tumor virus from the TIII strain (RIII-MuMTV). The virus that replicated in the human cells was characterized as a mouse virus by immunofluorescence, electron microscopy and the presence of a specific RNA-directed DNA polymerase. The cells themselves were human as per the karyotype and isoenzyme migration patterns. It is concluded that human cells are susceptible to the mouse mammary tumor virus and can, eventually, support its replication.
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PMID:A human breast tumor cell line (BT-474) that supports mouse mammary tumor virus replication. 9 35

Cultured synovial cells from 8 patients with rheumatoid arthritis (RA) and 7 subjects without joint disease were assayed and comapred for RNA-directed and DNA-directed DNA polymerase activity. No activity was found in either RA or control specimens using a synthetic RNA template that specificically detects oncornavirus RNA-directed DNA polymerase. The DNA-directed DNA polymerase activity of RA specimens was increased (P less than 0.10) in the high-speed pellet fraction of cell lysates. The possible relationship of these finding to virus infection in RA is disscussed.
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PMID:DNA polymerase activity of cultured rheumatoid synovial cells. 16 46

In vitro transcription of the avian tumor virus RNA by RNA-directed DNA polymerase is initiated on the unique cellular 4S RNA. Previous studies have shown that on the average there is one such RNA primer hydrogen bonded to each viral 35S RNA. The present study confirms that finding and demonstrates that, at least for the majority of 35S RNA molecules, the primer is bound at a site close to the 5'-terminus.
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PMID:Site on the RNA of an avian sarcoma virus at which primer is bound. 16 90

Analyses of the DNA polymerase present in the inner mitochondrial membrane and matrix fraction of the mitochondria isolated from Rous sarcoma cells and chick embryo cells, and in the lysate of Rous sarcoma virus were performed, using a modification of the thin-layer gel filtration on Sephadex G-150 superfine. The method allowed the simultaneous determination of the molecular weight of the isolated enzymes. In the mitochondria or Rous sarcoma cells an RNA-directed DNA polymerase, activated by poly(rA): oligo (dT) synthetic duplex, was detected, with the same molecular weight as the reverse transcriptase isolated from Rous sarcoma virus. Such enzyme was not found in the mitochondria of chick embryo cells.
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PMID:Detection of RNA-instructed DNA polymerase in the mitochondria of Rous sarcoma cells using sephadex G-150 thin-layer gel filtration. 17 3

Initiation of transcription from the genome of avian sarcoma virus by RNA-directed DNA polymerase in vitro requires tRNAtrp as a primer. The tRNA is bound to the viral genome by a sequence of 16 contiguous nucleotides (U-C-A-C-G-U-C-G-G-G-G-U-C-A-C-Cp), beginning with the penultimate base at the 3' terminus of the primer and extending through the acceptor stem into loop IV of the tRNA. Consequently, the native conformation of the tRNA must be disrupted by the binding of primer to the viral genome. The binding sequence does not include two adjacent residues of pseudouridine in loop IV, which distinguish the primer from many other tRNAs, and the 3' terminal adenosine of primer may also be excluded from base pairing with the viral genome.
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PMID:Nucleotide sequence that binds primer for DNA synthesis to the avian sarcoma virus genome. 18 13

The DNAase digestion end-product of calf thymus DNA contains oligonucleotides that will function as primers for the efficient transcription into DNA of many naturally-occurring RNA's by purified avian sarcoma virus RNA-directed DNA polymerase. The labeled DNA transcripts so obtained are valuable as probes for molecular hybridization studies. Typical applications of the method include the efficient transcription into DNA of 18 and 28 S rRNA as well as the RNA's of avian sarcoma virus, polio virus, influenza virus, satellite tobacco necrosis virus and tobacco mosaic virus. In addition, when these primers are added to avian sarcoma virus particles that have been partially-disrupted with non-ionic detergent there is 6-fold stimulation of the endogenous RNA-directed DNA synthesis.
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PMID:Efficeint transcription of RNA into DNA by avian sarcoma virus polymerase. 18 18


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