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)

Oncornavirus-like particles of the "A" (both intracisternal and intracytoplasmic) and "B" or "C" (extracellular) types are produced by murine MOPC-460 myeloma cells. This communication describes a comparative study on tracisternal A and extracellular particles. Both types of particles contain an RNA-dependent DNA polymerase activity, traces of 35S and 70 S RNA in addition to larger amounts of degraded RNA, and proteins of approximately 76,000 and 45, 000 daltons. The 76,000-dalton proteins from intracisternal A and extracellular particles have the same cyanogen bromide peptides. Hybridization kinetic analysis indicates that the RNAs in the two particles are identical or very closely related and share partial homology with Moloney leukemia virus RNA. In contrast, the particles appear to have little or no relationship to murine mammary tumor virus as judged by several different criteria. Electron microscope studies indicate that the extracellular particles arise from the budding of core components through the plasma membrane. These results suggest that the intracisternal A and extracellular oncornavirus-like particles produced by MOPC-460 cells are closely related.
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PMID:Relationships between intracisternal type A and extracellular oncornavirus-like particles produced in murine MOPC-460 myeloma cells. 5 64

Ethidium bromide (2,3-diamino-5-ethyl-6-phenylphenanthridinium bromide) significantly inhibited the RNA-dependent DNA polymerase of types A and C particles isolated from transplanted adenovirus 12-induced tumors of CBA mice. It was also cytotoxic for an established in vitro line of adenovirus 12-induced tumor cells of CBA mice and caused cell death, inhibition of [3H]thymidine uptake, and a significant reduction of cells in metaphase. Ethidium bromide significantly inhibited the in vivo growth of transplanted adenovirus 12-induced tumor cells of CBA mice, simian virus 40-induced tumor cells of hamsters, and murine leukemia virus-induced lymphoma cells of BALB/c mice. The compound may have exerted the antitumor activity by selectively affecting oncornavirus in the tumor cells.
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PMID:Effect of ethidium bromide on transplanted virus-induced tumor cells. 6 62

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

We have used analysis of ethidium-bromide-stained reverse transcriptase-polymerase chain reaction (RT-PCR) products to assess the effects of X-chromosome inactivation during spermatogenesis in the mouse. RT-PCR was performed on total RNA from eight different spermatogenic cell types, including premeiotic spermatogonia, meiotic spermatocytes, and postmeiotic spermatids, to detect transcripts from five different X-linked structural genes (Pgk-1, Zfx, Pdha-1, Hprt, and Phka) and two autosomal genes (Pgk-2 and beta-actin). Relative intensities of ethidium-bromide-stained RT-PCR products representing transcripts from each gene in each cell type were analyzed by densitometry using the Image program (version 1.4, NIH), and normalized against beta-actin values. These results suggest a coordinate inactivation of the X-linked loci at the onset of meiosis, followed by variable rates of decline of corresponding transcript levels reflecting differential mRNA stabilities and/or leaky expression after inactivation. Technically, these results indicate that analysis of ethidium-bromide-stained RT-PCR products can be used to provide a "semiquantitative" indication of relative levels of specific transcripts in a developing cell lineage without using radioactive probes to quantitate these products.
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PMID:Semiquantitative analysis of X-linked gene expression during spermatogenesis in the mouse: ethidium-bromide staining of RT-PCR products. 128 26

The reverse transcriptase (RT) of human immunodeficiency virus type 1 (HIV-1) is one of the main targets in approaches to the chemotherapy of AIDS. A detailed knowledge of structure-function relationships of this enzyme is a prerequisite for rational drug design. We have used monoclonal antibodies as tools to identify functionally important regions of the protein. The preparation of 23 murine monoclonal antibodies (mAb) against HIV-1 reverse transcriptase and their different effects on the enzyme are described. The interaction of purified mAbs with HIV-1 RT was demonstrated by enzyme-linked immunosorbent assay (ELISA), Western blots, and high performance liquid chromatography size exclusion chromatography. One of the antibodies also recognized recombinant HIV-2 RT. Antibody binding epitopes on HIV-1 RT were analyzed by immunoblotting using cyanogen bromide fragmented RT, C-terminally truncated mutants, and a peptide ELISA employing 15-mer synthetic overlapping peptides spanning nearly the complete polypeptide chain. The epitopes were mapped within three domains corresponding to amino acids 200-230, 300-428, and 528-560. Two mAbs show neutralizing properties on enzymatic functions of RT. One affects the polymerase activity and to a certain degree the RNase H activity of the enzyme, whereas the other inhibits the latter activity exclusively. mAb 28, which blocks the polymerase activity, interferes with the nucleotide binding region of RT, as shown by fluorescence spectroscopy using a labeled template/primer complex. By investigating the antibody effects on dimer formation of the heterodimeric enzyme, three domains corresponding to amino acids 230-300, 350-428, and residues around amino acid 540 involved in protein-protein interactions were localized.
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PMID:Structure-function relationships of HIV-1 reverse transcriptase determined using monoclonal antibodies. 137 37

BamHI-digested Biomphalaria glabrata DNA contains a repetitive 2.0-kb fragment which is readily discernible by ethidium bromide staining. We present evidence that this repetitive element is related at both the nucleotide and amino acid levels to long interspersed nuclear element (LINE)-like transposons. Although comparable elements have been described in several invertebrates, this is the first report of a molluscan homologue. In common with LINE transposons, an open reading frame in the B. glabrata element shows significant homology to reverse transcriptase--a feature believed to allow the dissemination of these elements in the eukaryotic genome.
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PMID:Identification of a repetitive element in the snail Biomphalaria glabrata: relationship to the reverse transcriptase-encoding sequence in LINE-1 transposons. 138 Sep 40

Various 3-substituted 3'-azido-3'-deoxythymidine analogs (2a-i) were prepared by the reaction of 3'-azido-3'-deoxythymidine (1), AZT with N,N-dimethylformamide dialkylacetal or alkyl bromide in the presence of base and their activities against human-immunodeficiency virus type-1 (HIV-1) were evaluated. The corresponding 5'-triphosphate analogs (9) were also synthesized in order to examine inhibition of HIV-1 reverse transcriptase activity. Beyond expectation, some N3-derivatives of AZT were found to reserve the anti-HIV-1 activity to some extent. Among the compounds (2a-i) obtained, 3-allyl-AZT (2e) was the most active against HIV-1 replication in MT-4 cells in vitro with an EC50 value of 0.9 microM. 3-Allyl-AZT 5'-triphosphate (9e), however, exhibited no inhibition of HIV-1 reverse transcriptase activity.
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PMID:Synthesis and anti-human immunodeficiency virus type 1 (HIV-1) activity of 3-substituted derivatives of 3'-azido-3'-deoxythymidine (AZT), and inhibition of HIV-1 reverse transcriptase by their 5'-triphosphates. 138 96

Prolactin receptor (PRL-R) mRNAs exist in several tissues where prolactin is known to act including the liver, testes, prostate, ovary, mammary gland, adrenal gland and kidney. PRL also acts at the level of the hypothalamus and pituitary gland to feed back and regulate its own secretion and the secretion of other anterior pituitary hormones. Therefore, we hypothesized that PRL-R mRNA would exist in these target tissues as well. Total RNA was extracted from rat anterior and medial basal hypothalamus, anterior and posterior pituitary gland, cerebral cortex, skeletal muscle and liver. After reverse transcribing total RNA with Murine-MLV reverse transcriptase and random or oligo(dT) pmers, the polymerase chain reaction (PCR) was performed. PCR products were then analyzed by ethidium bromide staining. Using primers that flanked the coding region for the extracellular binding domain we detected PRL-R mRNA in the anterior and medial basal hypothalamus, anterior and posterior pituitary gland, as well as in the liver, but not in the cerebral cortex or skeletal muscle. In addition, when we used primers that distinguish the long and short forms of the PRL-R mRNA, both forms of the PRL-R mRNA were detectable in the same tissues. Our data suggest that PRL may feed back at the level of the hypothalamus and pituitary gland through the same short and/or long PRL-R mRNA that mediate PRL action in the peripheral tissues.
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PMID:Detection of prolactin receptor (PRL-R) mRNA in the rat hypothalamus and pituitary gland. 153 21

Wheat DNA polymerase A has been purified from wheat germ. The previous purification procedure (Castroviejo, M. et al. (1979) Biochem. J. 181, 183-191; Tarrago-Litvak, L. et al. (1975) FEBS Lett. 59, 125-130), has been improved leading to a higher degree of purity. Several biochemical properties of the enzyme are described. Interestingly, wheat DNA polymerase A is able to copy natural poly(A)+ mRNA into cDNA, in a way that is similar to that of the human immunodeficiency virus reverse transcriptase (HIV-RT). All four dXTP and the oligo dT primer were required for cDNA synthesis. The cDNA product was completely digested in the presence of DNase I and predigestion of the mRNA template with RNase decreased dramatically the cDNA synthesis. The animal DNA polymerase gamma can not copy natural mRNA. Substances, known to alter the enzymatic activities have been used to compare enzymes properties. In the presence of glycerol, ethidium bromide or spermine, wheat DNA polymerase A, HIV-RT and DNA polymerase gamma behave similar and they differ from animal DNA polymerase alpha. Nevertheless, DNA polymerase A is more resistant than HIV-RT and DNA polymerase gamma to the chain terminator ddTTP, while the wheat enzyme is more inhibited than DNA polymerase gamma but more resistant than HIV-RT in the presence of N3-TTP.
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PMID:Wheat embryo DNA polymerase A reverse transcribes natural and synthetic RNA templates. Biochemical characterization and comparison with animal DNA polymerase gamma and retroviral reverse transcriptase. 169 Oct 20

Purified recombinant reverse transcriptase (RT) from human immunodeficiency virus type 1 (HIV-1) was used to raise 21 monoclonal antibodies with anti-RT specificities. The antibodies were characterized using Western blotting against native virus and recognized either the p66 or p66, p51 components of RT. Further immunoblotting using either cyanogen bromide fragmented RT or truncated mutants of RT along with cross-competition studies enabled the location of various immunogenic regions of RT to be identified. Three antibodies recognized a linear epitope in the N-terminal region (amino acids 128-176). Also, a neutralizing RT antibody recognized a conformational epitope in this region. Three monoclonals had epitopes mapped to linear sequences in the RNase H region at the C-terminus of the RT. Another neutralizing antibody, also requiring folding of the RT protein had its epitope more centrally located (231-353). Of the remaining 13 monoclonals, 7 were roughly located in the C-terminal region and required folding of the protein for epitope recognition and only three of the remaining six could be mapped to conformational epitopes in N-terminal and central regions of the RT. None of the antibodies tested recognized HIV-2 RT products p68 and p55 in Western blot.
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PMID:Monoclonal antibodies define linear and conformational epitopes of HIV-1 pol gene products. 171 17


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