Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| proteases from human immunodeficiency virus and avian myeloblastosis virus show distinct specificities in hydrolysis of multidomain protein substrates. | the virally encoded proteases from human immunodeficiency virus (hiv) and avian myeloblastosis virus (amv) have been compared relative to their ability to hydrolyze a variant of the three-domain pseudomonas exotoxin, pe66. this exotoxin derivative, missing domain i and referred to as lyspe40, is made up of a 13-kilodalton nh2-terminal translocation domain ii connected by a segment of 40 amino acids to enzyme domain iii of the toxin, a 23-kilodalton adp-ribosyltransferase. hiv protease hydrolyzes ... | 1990 | 2161935 |
| captan binding to avian myeloblastosis virus reverse transcriptase and its effect on rnase h activity. | the inhibitor captan (n-trichloromethylthio-4-cyclohexen-1,2-dicarboximide) was used to explore the ribonuclease h (rnase h) active site of avian myeloblastosis virus (amv) reverse transcriptase. gel permeation chromatography of purified enzyme showed that [14c]captan bound to the alpha subunit in a ratio of 10:1 and to a 32,000 d polypeptide in a ratio of 4:1. neither the alpha beta nor the beta subunit bound [14c]captan. the binding of 5 of the captan molecules was prevented by preincubating e ... | 1990 | 2166233 |
| 1 alpha,25-dihydroxyvitamin d3 regulates the expression of carbonic anhydrase ii in nonerythroid avian bone marrow cells. | 1 alpha,25-dihydroxyvitamin d3 [1,25(oh)2d3], the active metabolite of the steroid hormone vitamin d, is a potent regulator of macrophage and osteoclast differentiation. the mature osteoclast, unlike the circulating monocyte or the tissue macrophage, expresses high levels of carbonic anhydrase ii (caii). this enzyme generates protons and bicarbonate from water and carbon dioxide and is involved in bone resorption and acid-base regulation. to test whether 1,25(oh)2d3 could induce the differentiat ... | 1990 | 2166957 |
| [the tissue specificity of the expression of the avian sarcoma-leukosis complex viruses]. | 1990 | 2174768 | |
| alternative splicing of rnas transcribed from the human c-myb gene. | an alternative splicing event in which a portion of the intron bounded by the ve6 and ve7 exons with v-myb homology is included as an additional 363-nucleotide coding exon (termed e6a or coding exon 9a) has been described for normal and tumor murine cells that express myb. we show here that this alternative splicing event is conserved in human c-myb transcripts. in addition, another novel exon (termed e7a or coding exon 10a) is identified in human c-myb mrnas expressed in normal and tumor cells. ... | 1990 | 2188096 |
| two distinct and frequently mutated regions of retinoblastoma protein are required for binding to sv40 t antigen. | the retinoblastoma susceptibility gene (rb) encodes a phosphoprotein of 110 kd (pp110rb) that forms specific complexes with sv40 t antigen and the transforming proteins of several other dna tumor viruses. interaction with rb is thought to contribute to transformation by these viruses as demonstrated by genetic analyses. to help understand the function of these interactions, the regions of rb that are involved in binding to t have been mapped. an in vitro protein synthesis system capable of produ ... | 1990 | 2189724 |
| proteolytic cleavage of microtubule-associated proteins by retroviral proteinases. | aspartic proteinases from human immunodeficiency virus type 1 (hiv-1) and avian myeloblastosis virus (amv) were found to interfere with microtubule assembly. preincubation of the proteinases with purified brain microtubule proteins (tubulin and microtubule-associated proteins) at low ionic strength (ph 6.8), completely inhibited microtubule assembly. analysis of microtubule proteins after incubation with proteinase showed no effect on tubulin but extensive cleavage of the microtubule-associated ... | 1990 | 2212989 |
| removal of 3'-oh-terminal nucleotides from blunt-ended long terminal repeat termini by the avian retrovirus integration protein. | the avian myeloblastosis virus integration protein (in) was capable of removing a specific set of 3'-oh-terminal nucleotides from blunt-ended long terminal repeat (ltr) substrates which resembled linear viral dna in vivo. the 3'-oh-recessed ends map to the in vivo site of integration on linear viral dna. the linear dna plasmid substrate was formed by the generation of a unique drai restriction enzyme site (ttt/aaa) at the circle junction of a 330-bp tandem ltr-ltr insert. in preferentially relea ... | 1990 | 2214031 |
| the absence of a m7g cap on beta-globin mrna and alfalfa mosaic virus rna 4 increases the amounts of initiation factor 4f required for translation. | beta-globin mrna and alfalfa mosaic virus (amv) rna 4, two naturally capped mrnas, and satellite tobacco necrosis virus (stnv) rna, a naturally uncapped mrna, were prepared by in vitro transcription with and without a 5' m7g cap structure (m7g(5')ppp(5')n). the translation of the capped and uncapped forms of these mrnas was measured in a crude s30 system and a partially purified system from wheat germ. in the s30 system the uncapped forms of beta-globin mrna and amv rna 4 are much less active (g ... | 1990 | 2246243 |
| the nucleocapsid protein isolated from hiv-1 particles binds zinc and forms retroviral-type zinc fingers. | the role of zinc in retroviral gag protein function has been addressed through the application of high-resolution nuclear magnetic resonance spectroscopy to samples of the nucleocapsid protein (ncp, p7) isolated directly from infectious hiv-1 particles. unlike reports for the ncp from avian myeloblastosis virus (amv) particles [jentoft et al. (1988) proc. natl. acad. sci. u.s.a. 85, 7094], we find that the hiv-1 ncp binds 2 equiv of zinc tightly and stoichiometrically. two-dimensional nmr spectr ... | 1990 | 2261434 |
| interactions at the nucleic acid binding site of the avian retroviral nucleocapsid protein: studies utilizing the fluorescent probe 4,4'-bis(phenylamino)(1,1'-binaphthalene)-5,5'-disulfonic acid. | the structural and functional properties of the nucleocapsid (nc) protein of the avian myeloblastosis virus were examined by steady-state fluorescence and fluorescence anisotropy measurements of the complex between the nc and the extrinsic fluorophore 4,4'-bis(phenylamino)(1,1'-binaphthalene)-5,5'-disulfonic acid (bis-ans). the intrinsic fluorescence of bis-ans is enhanced many fold upon forming a complex with the nc. between 2 and 10 molecules of bis-ans bind strongly to the nc, with an overall ... | 1990 | 2261456 |
| mutations in v-myb alter the differentiation of myelomonocytic cells transformed by the oncogene. | chick myelomonocytic cells transformed by the v-myb oncogene-containing viruses e26 and amv differ in that the former resemble myeloblasts and express the v-myb-regulated granulocyte-specific mim-1 gene, while the latter resemble monoblasts and are mim-1 negative. we constructed a series of amv-e26 chimeras and localized the critical differences between these viruses to three point mutations within the second repeat of the v-myb dna binding domain. these three positions are altered in the v-myb ... | 1990 | 2261644 |
| yeast precursor ribosomal rna. molecular cloning and probing the higher-order structure of the internal transcribed spacer i by kethoxal and dimethylsulfate modification. | plasmids were constructed in which a hindiii fragment of rdna (6.4 x 10(3) base-pairs) was inserted into vectors pgem-1 and 2 in both orientations. the dna insert encoded the yeast 35 s precursor rrna beginning 180 bases upstream from the 5' end of the mature 18 s rrna and ending 289 bases beyond the 3' end of the mature 25 s rrna. the precursor rrna molecules produced in vitro consisted of 6430 nucleotides, with about 15 residues derived from the gemini vector on both ends. the general extent o ... | 1990 | 2407850 |
| inhibition of reverse transcriptase by limocrocin. | 1985 | 2410398 | |
| enzyme inhibition. viii: mode of inhibition of reverse transcriptase activity by analogues, isomers, and related alkaloids of coralyne. | coralyne analogues, isomers, and related alkaloids were examined as inhibitors of reverse transcriptase of rna tumor viruses in the presence of polyriboadenylic acid-oligodeoxythymidylic acid (poly ra.oligo dt), polydeoxyadenylic acid-oligodeoxythymidylic acid (poly da.oligo dt), polyribocytidylic acid-oligodeoxyguanylic acid (poly rc.oligo dg), activated calf thymus dna, and 70s rna template primers. the inhibition of the reverse transcriptase exhibited by analogues, isomers, and related alkalo ... | 1985 | 2411910 |
| formycin 3' end modified trnatrp. recognition by avian myeloblastosis virus reverse transcriptase and primer function. | primer trnatrp has been modified at the 3' end by adenosine analogues: 2'deoxyadenosine, 3'deoxyadenosine, 3' amino-3' deoxyadenosine and formycin. aminoacylation of modified trnatrp with cognate aminoacyl-trna synthetase and primer function for dna synthesis catalyzed by amv reverse transcriptase have been studied. the trnatrp was able to accept tryptophan but did not initiate the dna synthesis directed by 35s amv rna. recognition of modified trnatrp by amv reverse transcriptase was not affecte ... | 1985 | 2412559 |
| inhibitory effect of tannins on reverse transcriptase from rna tumor virus. | twenty-four tannins and related compounds were examined for inhibition against reverse transcriptase from rna tumor virus. hydrolyzable tannins showed a potent inhibitory effect comparable to nitidine, in the presence of polyadenylic acid-oligothymidylic acid as a template-primer. a lesser inhibitory activity was observed for the monomeric ellagitannins, gallotannins, and nitidine using polycytidylic acid-oligodeoxyguanylic acid as a template-primer, whereas the inhibitory activity of dimeric el ... | 1985 | 2413172 |
| developmental regulation of c-myb in normal myeloid progenitor cells. | hematopoietic tissues and some leukemic cell lines express elevated levels of c-myb transcripts. we have separated a subpopulation of chicken embryo yolk sac cells that represents about 5% of the yolk sac hematopoietic cells and appears to contain all of the detectable c-myb transcripts. the level of myb expression in this cell population is higher than previously reported for any normal cell population and is in the range of that found in cells transformed by avian myeloblastosis virus and e26 ... | 1985 | 2413449 |
| rapid determination of 16s ribosomal rna sequences for phylogenetic analyses. | although the applicability of small subunit ribosomal rna (16s rrna) sequences for bacterial classification is now well accepted, the general use of these molecules has been hindered by the technical difficulty of obtaining their sequences. a protocol is described for rapidly generating large blocks of 16s rrna sequence data without isolation of the 16s rrna or cloning of its gene. the 16s rrna in bulk cellular rna preparations is selectively targeted for dideoxynucleotide-terminated sequencing ... | 1985 | 2413450 |
| functional studies on the egf receptor with an antibody that recognizes the intracellular portion of the receptor. | an antibody against the human epidermal growth factor receptor (egf), capable of activating its tyrosine kinase has been produced. antibody 2913 recognizes only the cytoplasmic portion of the egf receptor in a431 carcinoma cells, in normal human fibroblasts, and in a variety of other human tumor cell lines (xu, y.-a., richert, n., ito, s., merlino, g. t., and pastan, i. (1984) proc. natl. acad. sci. u. s. a. 81, 7308-7313). indirect immunofluorescence and electron microscopy show that the antibo ... | 1986 | 2418017 |
| biological properties of streptonigrin derivatives. ii. inhibition of reverse transcriptase activity. | 1986 | 2420775 | |
| inhibition by sakyomicin a of avian myeloblastosis virus reverse transcriptase and proliferation of aids-associated virus (htlv-iii/lav). | in the course of screening for inhibitors of reverse transcriptase, we have isolated an inhibitor from a strain of nocardia and identified it as sakyomicin a. the antibiotic blocks avian myeloblastosis virus reverse transcriptase reaction: ic50 was ca. 30 micrograms/ml by the method employed. the drug affects proliferation of htlv-iii/lav in htlv-i-carrying mt-4 cells: ca. 60% inhibition was observed at an antibiotic concentration of 1.0 microgram/ml and ca. 20% inhibition at 0.1 microgram/ml, a ... | 1986 | 2422146 |
| role of the naphthoquinone moiety in the biological activities of sakyomicin a. | the naphthoquinone moiety was proven to be essential to the biological activities of sakyomicin a using various naphthoquinone derivatives. among the naphthoquinones tested, juglone (5-hydroxy-1,4-naphthoquinone) which resembles the partial structure of sakyomicin a was the most active in cytotoxicity against murine lymphosarcoma l5178y cells, electron acceptor function in the oxidation of nadh by clostridium kluyveri diaphorase or rat liver mitochondria and inhibition against avian myeloblastos ... | 1986 | 2423491 |
| differential effects of captan on dna polymerase and ribonuclease h activities of avian myeloblastosis virus reverse transcriptase. | captan was used as an inhibitor of avian myeloblastosis virus reverse transcriptase to study the polymerase and rnase h catalytic activities. with purified enzyme, rnase h activity was 10-fold more sensitive to captan than was either the dna-dependent or rna-dependent dna polymerase activity. inhibition of the rna-dependent polymerase activity could be prevented by dttp. conversely, inhibition of this polymerase activity was enhanced by template/primer. the calculated kdttp of the uninhibited re ... | 1986 | 2424494 |
| mapping of the displacement loop within the nucleotide sequence of xenopus laevis mitochondrial dna. | the mtdna of the african frog, xenopus laevis, has a triple-stranded displacement loop (d-loop) structure at the origin of heavy strand dna replication. the major species of displacing strands has a length of 1670 nucleotides, approximately 3 times the length of mouse or human d-loop mtdna strands. we report experiments that precisely map the termini of the d-loop strand within a revised sequence of the origin region. analysis of d-loop mtdna strands labeled in vitro at the 5' end using polynucl ... | 1986 | 2424898 |
| detection of antibodies to avian reverse transcriptase by indirect elisa. | an improved indirect elisa test for detection of antibodies to the reverse transcriptase (revertase) is described. the sensitivity of the revertase elisa test was compared to that of the revertase inhibition test. serum samples of various origin and sera of specific pathogen free (spf) hens were examined for the revertase antibodies. the presence of these antibodies in the sera of spf chickens is discussed. | 1986 | 2425612 |
| ppi analogs as inhibitors of human t-lymphotropic virus type iii reverse transcriptase. | twenty-six ppi analogs were tested for inhibitory effects on human t-lymphotropic virus type iii reverse transcriptase. the structural requirements for inhibition and mechanism of action of the most active inhibitors have been investigated. foscarnet (phosphonoformic acid) was the most potent inhibitor of human t-lymphotropic virus type iii reverse transcriptase with 50% inhibition at 0.5 microm. the mechanism was a noncompetitive type of inhibition of a (riboadenylic acid)n . (deoxythymidylic a ... | 1986 | 2425731 |
| transforming potential of the v-myb oncogene from avian myeloblastosis virus: alterations in the oncogene product may reveal a new target specificity. | transfection of brown leghorn chicken embryo fibroblasts by dna containing v-myb sequences cloned either in a complete amv proviral dna or in a retroviral derived vector has led to the isolation of two kinds of transformed cells. a characterization of the proviral sequences retained and expressed in these transformed cells revealed that they contained either new or altered v-myb-related rna species. the experiments presented in this paper also show that both types of transformants expressed trun ... | 1986 | 2427128 |
| characterization, sequence, and expression of the cloned human neuropeptide y gene. | the human neuropeptide y (npy) gene was isolated from a human genomic dna library. the transcription unit spans approximately 8 kilobase pairs and is interrupted by three intervening sequences. the first exon contains only nontranslated dna. the site where transcription initiates was determined by primer extension analysis using a primer derived from a human cdna, pheochromocytoma rna and avian myeloblastosis virus reverse transcriptase. a tata-like sequence and a caat-like sequence occur 25 and ... | 1986 | 2427515 |
| misincorporation by amv reverse transcriptase shows strong dependence on the combination of template and substrate nucleotides. | we have carried out a systematic investigation of the efficiency of misincorporation by avian myeloblastosis virus reverse transcriptase with all possible combinations of dntp substrate, template nucleotide, and the nucleotide at the 3' terminus of the primer. a series of synthetic oligonucleotide primers were annealed to single stranded m13 dna templates, and a single dntp was misincorporated at the primer 3' end using amv reverse transcriptase. the proportion and pattern of misincorporation an ... | 1986 | 2429257 |
| nucleoside 5'-triphosphates modified at sugar residues as substrates for calf thymus terminal deoxynucleotidyl transferase and for amv reverse transcriptase. | terminal deoxynucleotidyl transferase from calf thymus and rna-directed dna polymerase (reverse transcriptase) from the avian myeloblastosis virus catalyze the incorporation of 3'-amino-2',3'-dideoxynucleoside 5'-triphosphates, as well as some of their 3'-derivatives, 3'-amino-3'-deoxyarabinonucleoside 5'-triphosphates and some other nucleoside 5'-triphosphates modified at sugar residues. after incorporation of the appropriate 5'-mononucleotide residue into the dna, further chain elongation is b ... | 1986 | 2429703 |
| direct identification of small sequence changes in chromosomal dna. | dideoxynucleotide chain termination sequencing has been applied directly to genomic dna templates by annealing radiolabeled oligodeoxynucleotide primers to unique sites in total yeast dna and extending with avian myoblastosis virus (amv) reverse transcriptase. the technique is used here to confirm the introduction of selectively altered trna genes into the saccharomyces cerevisiae genome by gene replacement. | 1986 | 2429900 |
| rna-dependent dna polymerase activity in paramecium tetraurelia: what for? | protein extracts from the protozoan ciliate paramecium tetraurelia revealed high levels of rna-dependent dna polymerase activity (reverse transcriptase). stable and constant during the somatic phase of the cell cycle, the reverse transcriptase activity quickly diminished following the completion of the sexual phases of the cell cycle: conjugation and autogamy. the paramecium reverse transcriptase presented a number of common features with retroviral polymerases: ability to copy synthetic templat ... | 1987 | 2435548 |
| screening for inhibitors of avian myeloblastosis virus reverse transcriptase and effect on the replication of aids-virus. | 1987 | 2435692 | |
| inhibition by doxorubicin of human immuno-deficiency virus (hiv) infection and replication in vitro. | 1987 | 2437093 | |
| inhibition of viral reverse transcriptase by 2',5'-oligoadenylates. | viral reverse transcriptase activity was inhibited in a concentration dependent manner by 2',5'-oligoadenylate. kinetically this inhibition was of a mixed type where 2',5'-oligoadenylate was not strictly competitive with dttp. the potency of inhibition was more marked in the absence than in the presence of sulfhydryl agents. 2',5'-oligoadenylate had no effect on dna-dependent e. coli dna polymerase and was much less active against mammalian dna polymerases. this is the first report of reverse tr ... | 1987 | 2439079 |
| properties of 2',3'-dideoxy-2',3'-dehydrothymidine 5'-triphosphate in terminating dna synthesis catalyzed by several different dna polymerases. | 2',3'-dideoxy-2',3'-dehydrothymidine 5'-triphosphate (dddttp) shows termination substrate properties in the dna synthesis catalyzed by e. coli dna polymerase i kf, rat liver dna polymerase beta, reverse transcriptases of avian myeloblastosis virus and raus sarcoma virus and calf thymus terminal deoxynucleotidyl transferase. this implies that the mononucleotide residue of dddttp incorporates into 3'-termini of newly synthesized dna chains. however, dddttp has no influence on the dna synthesis cat ... | 1987 | 2439382 |
| monoclonal antibodies against rna-dependent dna polymerase from myeloblastosis-associated viruses. | two lines of hybridomas, rt-12 and rt-14, secreting monoclonal antibodies against the reverse transcriptase from myeloblastosis-associated viruses have been prepared. the monoclonal antibodies rt-12 and rt-14 specifically react with reverse transcriptase, as has been shown by radioimmunoassay and enzyme-linked immunoassay techniques after sds-page and blotting to nitrocellulose membranes. it has been shown that antigenic determinants for rt-12 and rt-14 are stable to sds denaturation, hence they ... | 1987 | 2439388 |
| different patterns of inhibition of avian myeloblastosis virus reverse transcriptase activity by 3'-azido-3'-deoxythymidine 5'-triphosphate and its threo isomer. | the two isomers 3'-azido-3'-deoxythymidine 5'-triphosphate (erythro-azt-tp) and 1-(3'-azido-2',3'-dideoxy-beta-d-xylofuranosyl)thymine 5'-triphosphate (threo-azt-tp) were studied as inhibitors of the reverse transcriptase activity of avian myelobastosis virus. kinetic analysis of the (ra)n x (dt)12-18 (a standard template primer complex of polyriboadenylate and oligodeoxythymidylate of indicated length)-directed reaction revealed that erythro-azt-tp was a competitive inhibitor with respect to dt ... | 1987 | 2440379 |
| comparative study on biological activities of heterocyclic quinones and streptonigrin. | thirteen heterocyclic quinones (5 quinoline quinones, 7 isoquinoline quinones, 1 indole quinone) were tested for their effects on avian myeloblastosis virus reverse transcriptase, growth of murine lymphoblastoma l5178y cells, respiration of rat liver mitochondria and oxidation of nadh by clostridium kluyveri diaphorase in comparison with those of streptonigrin, in which the quinoline quinone moiety is considered to play a crucial role. most of the quinoline quinones and isoquinoline quinones inh ... | 1987 | 2440840 |
| role of single-electron reduction potential in inhibition of reverse transcriptase by streptonigrin and sakyomicin a. | 1987 | 2440841 | |
| oligodeoxynucleotides containing synthetic abasic sites. model substrates for dna polymerases and apurinic/apyrimidinic endonucleases. | a synthetic procedure has been developed by which stable abasic sites are introduced into oligodeoxynucleotides at any desired position in the sequence. a modified tetrahydrofuran moiety, isosteric with 2'-deoxyribofuranose, serves as a structural analog of the natural apurinic/apyrimidinic site. we have also prepared oligodeoxynucleotides that lack cyclic structure at the abasic site but retain the carbon atoms of the phosphodiester backbone. these synthetic oligodeoxynucleotides are cleaved on ... | 1987 | 2440861 |
| dna damage at thymine n-3 abolishes base-pairing capacity during dna synthesis. | 3-methylthymine was synthesized into dna copolymers and deoxynucleoside triphosphate to study its effect on dna synthesis by the klenow fragment of escherichia coli polymerase i and avian myeloblastosis virus reverse transcriptase. both polymerases were greatly inhibited by template 3-methylthymine. in response to 3-methylthymine, misincorporation of dttp increased slightly, but occurred only at low levels consistent with spontaneous misincorporation in vitro. surprisingly, template 3-methylthym ... | 1987 | 2442169 |
| antiretroviral activity in a marine red alga: reverse transcriptase inhibition by an aqueous extract of schizymenia pacifica. | an aqueous extract from the marine red alga, schizymenia pacifica has been tested in a cell free system for its effect on reverse transcriptase from avian retrovirus (avian myeloblastosis virus), and mammalian retrovirus (rauscher murine leukemia virus). the extract inhibited reverse transcriptase from both these retroviruses but showed almost no effect, if any, on the activity of cellular dna polymerase alpha and rna polymerase ii in vitro. consequently it is unlikely to have an adverse effect ... | 1987 | 2442171 |
| synthesis and application of derivatizable oligonucleotides. | to investigate protein-dna interactions, we have synthesized a versatile phthalimide-protected 5-(3-aminopropyl)-2'-deoxyuridine nucleoside probe. the modified residue was incorporated into deoxyoligonucleotides by automated synthesis. the standard oligonucleotide workup also exposed the pendent amino group, which was found to react with either fluorescent labelling agents or, as detailed below, a photoactivatable cross-linking agent. in the dark, a strand with a photolabile group adjacent to th ... | 1987 | 2442728 |
| a system for rapid dna sequencing with fluorescent chain-terminating dideoxynucleotides. | a dna sequencing system based on the use of a novel set of four chain-terminating dideoxynucleotides, each carrying a different chemically tuned succinylfluorescein dye distinguished by its fluorescent emission is described. avian myeloblastosis virus reverse transcriptase is used in a modified dideoxy dna sequencing protocol to produce a complete set of fluorescence-tagged fragments in one reaction mixture. these dna fragments are resolved by polyacrylamide gel electrophoresis in one sequencing ... | 1987 | 2443975 |
| association of persistent synthesis of viral dna with macrophage accessory cell dysfunction induced by avian retrovirus myeloblastosis-associated virus of subgroup b inducing osteopetrosis in chickens. | this investigation concentrates on a regenerative anemia and immunosuppression occurring in the absence of osteopetrosis. polyclonal activation of t-cells was used as an in vitro test system to study immunosuppression induced by the avian myeloblastosis-associated virus of subgroup b inducing osteopetrosis [mav-2(o)]. t-cell unresponsiveness in vitro was attributed to a defect in an accessory cell function of the macrophage. counterflow centrifugation fractionation followed by mixing experiments ... | 1987 | 2444336 |
| [ability of 3'-substituted nucleoside phosphothioates to terminate dna synthesis catalyzed by various dna-polymerases]. | ability of some new substrates containing the 5'-alpha-thiotriphosphate residue to terminate the dna synthesis catalyzed by several dna polymerases has been investigated. the cell-free test system contained the m13mp10 phage single-stranded dna and a synthetic oligonucleotide primer. reverse transcriptase from avian myeloblastosis virus catalyzed termination of dna synthesis by 3'-azido-3'-fluoro- and 3'-amino-2',3'-dideoxythymidine-5'-(alpha-thio)triphosphates, whereas rat liver dna polymerase ... | 1987 | 2445356 |
| sulfation of polysaccharides generates potent and selective inhibitors of human immunodeficiency virus infection and replication in vitro. | the inhibitory effects of several polysaccharides, dextran, xylofuranan, and ribofuranan, and their sulfated counterparts on the infectivity and replication of human immunodeficiency virus (hiv) were examined by using an htlv-i-carrying cell line, mt-4, in vitro. dextran sulfate (mw 34 x 10(3], xylofuranan sulfate, and ribofuranan sulfate completely prevented hiv-induced cytopathic effects (cpe) at concentrations greater than 10 micrograms/ml and dextran sulfate (mw 7 x 10(3] at concentrations g ... | 1987 | 2447045 |
| hemin inhibits virion-associated reverse transcriptase of murine leukemia virus. | the virion-associated reverse transcriptase activity of rauscher murine leukemia virus was inhibited by freshly prepared hemin at a concentration of 10(-4) m. when the hemin solution was aged at room temperature for 5 days, the concentration of 50% inhibition decreased to as low as 10(-7) m. removal of o2 from the solution partially prevented the aging. the hemin inhibition was reversible and appears to be directed against the enzyme rather than the template. hemin did not inhibit the activity o ... | 1987 | 2447881 |
| purification and characterization of an avian myeloblastosis and human immunodeficiency virus reverse transcriptase inhibitor, sulfated polysaccharides extracted from sea algae. | a new reverse transcriptase (rt) inhibitor was extracted and purified from the red alga schizymenia pacifica. the chromatographic behavior and chemical properties of this sea algal extract (sae) suggest that it is a sulfated polysaccharide having a molecular weight of approximately 2,000,000. sae is composed of galactose (73%), sulfonate (20%), and 3,6-anhydrogalactose (0.65%). sae is a member of the lambda-carrageenan family, based on its infrared spectrum and products of hydrolysis. sae select ... | 1987 | 2449120 |
| the influence of a double-stranded hindrance on dna synthesis performed by dna polymerase alpha, t4 dna polymerase, dna polymerase i (klenow fragment) and amv reverse transcriptase. | the influence of a double-stranded region on dna synthesis performed by a series of dna polymerases on a single-stranded template was studied. two types of double-stranded hindrances were employed: a stable hairpin formed by the template alone and a region formed by the template and an extraneous oligonucleotide complementary to the template. while t4 and calf thymus alpha dna polymerases are strongly arrested at the beginning of either of the two double-stranded hindrances, the klenow fragment ... | 1988 | 2449362 |
| cuucgg hairpins: extraordinarily stable rna secondary structures associated with various biochemical processes. | the mrna of bacteriophage t4 contains a strikingly abundant intercistronic hairpin. within the 55 kilobases of known t4 sequence, the hexanucleotide sequence cttcgg is found 13 times in the dna strand equivalent to mrna sequences. in 12 of those occurrences, the sequence is flanked by inverted repeats predictive of rna hairpins with uucg in the loop. avian myeloblastosis virus reverse transcriptase, which can traverse hairpins of larger calculated stability, terminates efficiently at these cuucg ... | 1988 | 2449689 |
| characterization of the cdna synthesized by avian retrovirus reverse transcriptase using 35 s avian myeloblastosis virus rna and an exogenous bovine primer trna. | bovine trna(trp) can be partially hybridized to the avian myeloblastosis virus (amv) 35 s rna at 37 degrees c, in the presence of amv rna-dependent dna polymerase (reverse transcriptase). this template-primer complex is active in the synthesis of viral cdna. the size of the cdna products synthesized in the in vitro reconstituted amv system was determined by urea-polyacrylamide gel electrophoresis using a trna labelled at the 3'-end by yeast trna nucleotidyl transferase. the synthesized cdna has ... | 1988 | 2450786 |
| inhibition of avian myeloblastosis virus reverse transcriptase and its associated activities by daunomycin and adriamycin. | 1987 | 2452786 | |
| cytotoxic activity of daunomycin and adriamycin encapsulated in immunoliposomes against avian myeloblastosis virus-infected cells. | immunoliposomes were prepared using the antibody raised against the avian myeloblastosis virus envelope glycoprotein, gp80. adriamycin was encapsulated into immunoliposomes. more drug was delivered into target cells when the drug encapsulated in immunoliposomes was incubated with the cells. the drug encapsulated in immunoliposomes was able to inhibit the rna synthesis twice more than free drug in the virus-transformed myeloblasts. pre-treatment of cells with ammonium chloride, reversed the effec ... | 1988 | 2452826 |
| novel non-templated nucleotide addition reactions catalyzed by procaryotic and eucaryotic dna polymerases. | dna polymerases catalyze the addition of deoxyribonucleotides onto dna primers in a template-directed manner. the requirement for template instruction distinguishes these enzymes from other nucleotidyl transferases, such as terminal deoxynucleotidyl transferase, that do not utilize a template. an oligonucleotide substrate was used to characterize a novel, non-templated nucleotide addition reaction carried out by dna polymerases from a variety of procaryotic and eucaryotic sources. the products o ... | 1988 | 2460825 |
| fidelity of hiv-1 reverse transcriptase. | the human immunodeficiency virus type 1 (hiv-1) shows extensive genetic variation and undergoes rapid evolution. the fidelity of purified hiv-1 reverse transcriptase was measured during dna polymerization in vitro by means of three different assays. reverse transcriptase from hiv-1 introduced base-substitution errors in dna from the bacteriophage phi x174 amber3 at estimated frequencies of 1/2000 to 1/4000. analyses of misincorporation rates opposite a single template adenine residue showed that ... | 1988 | 2460924 |
| the accuracy of reverse transcriptase from hiv-1. | a study was conducted to determine the fidelity of dna synthesis catalyzed in vitro by the reverse transcriptase from a human immunodeficiency virus type 1 (hiv-1). like other retroviral reverse transcriptases, the hiv-1 enzyme does not correct errors by exonucleolytic proofreading. measurements with m13mp2-based fidelity assays indicated that the hiv-1 enzyme, isolated either from virus particles or from escherichia coli cells infected with a plasmid expressing the cloned gene, was exceptionall ... | 1988 | 2460925 |
| avian myeloblastosis virus reverse transcriptase is easier to use than the klenow fragment of dna polymerase i for labeling the 3'-end of a dna fragment. | the 3'----5' exonuclease activity of the klenow fragment operates in 3'-end labeling of dna fragments. in the presence of excess deoxyribonucleoside 5'-triphosphates (dntps), the 5'----3' polymerase activity is dominant over the exonuclease activity. however, in the presence of a small amount of dntps, the exonuclease activity removed deoxyribonucleoside 5'-monophosphate (dnmp) incorporated in the 3'-end of a dna strand by the polymerase activity. we found that the radioactivity of incorporated ... | 1988 | 2461116 |
| mechanism of inhibition of reverse transcriptase by quinone antibiotics. ii. dependence on putative quinone pocket on the enzyme molecule. | inhibition of avian myeloblastosis virus (amv) reverse transcriptase by natural and synthetic quinones including antibiotics could be accounted for by an oxidation-reduction reaction. the quinones were shown to function as electron acceptors as revealed by the catalytic oxidation of nadh by clostridium kluyveri diaphorase which was in excellent agreement with enzyme inhibition activity. the kinetics of inhibition of amv reverse transcriptase by three synthetic quinones with different core struct ... | 1988 | 2461354 |
| the fidelity of dna polymerases during in vitro replication of a template containing 5-bromouracil at a specific site. | the miscoding properties of a 5-bromodeoxyuridine (db) containing dna template during in vitro replication have been investigated. 5-bromodeoxyuridine was introduced site-specifically into the amber 16 codon of a 25-mer oligodeoxynucleotide representing part of the sequence of phi x174am16(+)dna. the db containing oligodeoxynucleotide served as a template for in vitro replication by dna polymerase alpha, dna polymerase i (escherichia coli) and amv reverse transcriptase. the amber 16 revertant as ... | 1989 | 2462557 |
| use of reverse transcription to determine the exact locations of psoralen photochemical crosslinks in rna. | we have studied the properties of avian myeloblastosis virus reverse transcriptase on escherichia coli 16s ribosomal rna that was known to contain a psoralen crosslink in a restricted region around residue 920. these crosslinked rna molecules were purified on the basis of loop size by gel electrophoresis. reverse transcription stopped at specific positions in the crosslinked molecules but not in control linear molecules. with the particular crosslink that was studied, at the earliest time of rev ... | 1988 | 2464291 |
| mapping of a small phosphopeptide at the carboxyterminus of the viral myb protein by monoclonal antibodies. | several myb-specific monoclonal antibodies were produced and their antigen recognition sites characterized using a series of bacterially expressed truncated myb proteins. the monoclonal antibodies were used for analysing the in vivo phosphorylation site of the oncogene protein from avian myeloblastosis virus (amv), p48v-myb. the p48v-myb protein labeled metabolically with [32p]orthophosphate was isolated from the amv-transformed chicken myeloblast cell line bm-2 by immunoaffinity chromatography. ... | 1989 | 2464784 |
| 3'-end labeling of dna fragments by amv-reverse transcriptase. | the efficiency on 3'-end labeling of dna fragments was compared between klenow fragment of dna polymerase i from e. coli and amv-reverse transcriptase. in the case of klenow fragment, the exonuclease activity of this enzyme rapidly removed the labeled dnmp incorporated in 3'-end of dna fragment by the polymerase activity of it. amv-reverse transcriptase caused no decrease of the labeled dnmp incorporated by the polymerase activity because it has no exonuclease activity. therefore, amv-reverse tr ... | 1988 | 2465535 |
| kinetic properties of poly (2'-o-methylcytidylic acid)-directed reverse transcriptase reaction. | poly (2'-o-methylcytidylic acid) is recognized as a template in reactions catalyzed by rna-dependent dna polymerases in the presence of mn2+ as divalent cation. we report that kinetic data obtained for dgtp and template under optimal experimental conditions in the reaction catalyzed by reverse transcriptase showed some similarities between the poly (2'-o-methylcytidylic acid)/mn2+ and polyribocytidylic acid/mg2+ systems. the reaction was inhibited by the action of n-ethylmaleimide and novobiocin ... | 1988 | 2465802 |
| comparative studies of the inhibitory properties of antibiotics on human immunodeficiency virus and avian myeloblastosis virus reverse transcriptases and cellular dna polymerases. | the inhibition of human immunodeficiency virus (hiv) reverse transcriptase by certain antibiotics and related compounds was studied in comparison with that of avian myeloblastosis virus (amv) reverse transcriptase and cellular dna polymerases alpha and beta. in general, compounds that inhibited hiv reverse transcriptase also inhibited amv reverse transcriptase. for example, 10 micrograms/ml of the isoquinoline quinones used in this study inhibited approximately 80% of the activity of reverse tra ... | 1989 | 2466028 |
| fidelity of two retroviral reverse transcriptases during dna-dependent dna synthesis in vitro. | we determined the fidelity of avian myeloblastosis virus and moloney murine leukemia virus reverse transcriptases (rts) during dna synthesis in vitro using the m13mp2 lacz alpha gene as a mutational target. both rts commit an error approximately once for every 30,000 nucleotides polymerized. dna sequence analysis of mutants generated in a forward mutation assay capable of detecting many types of errors demonstrated that avian myeloblastosis virus rt produced a variety of different mutations. the ... | 1989 | 2469002 |
| ribonuclease h activities associated with viral reverse transcriptases are endonucleases. | a series of test substrates have been synthesized to establish the effect of termini on the putative exoribonuclease h activity of reverse transcriptase. recombinant reverse transcriptase from human immunodeficiency virus, natural enzyme from avian myeloblastosis virus, and a known endonuclease, escherichia coli ribonuclease h, cleaved relaxed, circular, covalently closed plasmids in which 770 consecutive residues of one strand were ribonucleotides. the avian enzyme also deadenylated capped glob ... | 1989 | 2471188 |
| use of avian myeloblastosis virus reverse transcriptase at high temperature for sequence analysis of highly structured rna. | avian myeloblastosis virus reverse transcriptase (amv rt) is routinely used in the sequence analysis of rna and dna templates. we review the various methods for dealing with secondary structures that would otherwise result in premature termination or sequence compression. based on our experience in sequencing the 11-kb single-stranded rna genome of lymphocytic choriomeningitis virus, we have found that raising the reaction temperature above 47 degrees c is the simplest way to overcome template s ... | 1989 | 2473018 |
| nearest neighbor influences on dna polymerase insertion fidelity. | the kinetics of forming all possible single base substitution errors are measured for drosophila melanogaster dna polymerase alpha and avian myeloblastosis virus reverse transcriptase. seventeen sites along bacteriophage m13 dna are investigated so that effects of nearest neighbor base stacking on misinsertion kinetics can be evaluated. polymerase alpha appears to be more error prone than reverse transcriptase. polymerase alpha forms transversion mispairs at rates comparable to transition mispai ... | 1989 | 2474545 |
| feline immunodeficiency virus, a model for reverse transcriptase-targeted chemotherapy for acquired immune deficiency syndrome. | feline immunodeficiency virus (fiv), formerly called feline t-lymphotropic lentivirus, causes an immune deficiency in cats that is very similar to the acquired immune deficiency syndrome in humans (n. c. pedersen, e. m. ho, m. l. brown, and j. k. yamamoto, science 235:790-793, 1987). we have examined the reverse transcriptase of this virus to determine whether it is similar enough to the reverse transcriptase of the human immunodeficiency virus type 1 (hiv-1) to enable its use as a model for che ... | 1989 | 2475068 |
| spermine stimulates rna-dependent reverse transcriptase activity. | the polyamine spermine can not replace mg2+ in the reactions catalyzed by avian myeloblastosis virus reverse transcriptase. in the presence of suboptimal mg2+ concentrations, spermine enhanced the reverse transcriptase activities with viral 70 s rna and synthetic polyriboadenylic acid as templates, about 4-fold and 2-fold, respectively. a similar effect occurred in the polyriboadenylic acid-directed reaction using mn2+ as divalent cation. on the other hand, no stimulation by spermine was observe ... | 1989 | 2476130 |
| inhibition of avian myeloblastosis virus reverse transcriptase by flavones and isoflavones. | 1989 | 2478516 | |
| intrinsic properties of reverse transcriptase in reverse transcription. associated rnase h is essentially regarded as an endonuclease. | the intrinsic properties of reverse transcriptase in reverse transcription were studied using a synthetic, partial ovalbumin mrna with a synthetic dna oligonucleotide annealed to the 3'-end of the rna as a model substrate. with or without concomitant cdna synthesis, the rnase h activity of avian myeloblastosis virus (amv)-reverse transcriptase cleaved the substrate at a site which would leave a hybrid of between 7 and 14 base pairs between the 3' termini of the rna and dna oligonucleotide. varia ... | 1989 | 2478553 |
| inhibition of reverse transcriptases by flavonoids. | selected naturally occurring flavonoids were shown to inhibit three reverse transcriptases (rt): avian myeloblastosis (amv) rt, rous-associated virus-2 (rav-2) rt and maloney murine leukemia virus (mmlv) rt when poly (ra)oligo(dt)12-18 or rabbit globin mrna were used as template. amentoflavone, scutellarein and quercetin were the most active compounds and their effect was concentration-dependent. the enzymes exhibited differential sensitivity to the inhibitory effects of the flavonoids. the comp ... | 1989 | 2480745 |
| the ets sequence is required for induction of erythroblastosis in chickens by avian retrovirus e26. | e26 is a replication-defective avian retrovirus that causes an erythroblastic leukemia in vivo and transforms hematopoietic precursor cells of both the erythroid and the myeloid lineages in vitro. the e26 genome contains two sets of cell-derived sequences, ets and myb. myb sequences are also present in avian myeloblastosis virus, which transforms myeloblasts exclusively. to determine whether the ets sequence is responsible for the erythroid specificity of e26, we analyzed the transforming activi ... | 1989 | 2535740 |
| avian retroviral protease and cellular aspartic proteases are distinguished by activities on peptide substrates. | the avian sarcoma/leukemia virus protease (pr), purified from avian myeloblastosis virus has a native molecular mass of 26 kda, suggesting a dimer structure. the enzymatic activity of pr has been characterized using synthetic peptide substrates. pr is most active at ph 5.5, 35 degrees c and 2-3 m nacl. under these conditions pr cleaves decapeptides which are resistant in low ionic strength. this high, nonphysiological, salt concentration also increases the proteolytic activity of a cellular aspa ... | 1989 | 2536748 |
| phosphorylation of avian retrovirus matrix protein by ca2+/phospholipid-dependent protein kinase. | the matrix protein from avian myeloblastosis virus and the rous sarcoma virus, prague c strain, is a phosphoprotein. a comparison of the amino acid sequences shows these phosphoproteins are very similar. the sites of phosphorylation of the matrix protein purified from virions are identified as serine residues 68 and 106. treatment with purified rabbit skeletal-muscle protein phosphatase 1 or 2a, selectively releases phosphate from serine 68, while alkali treatment releases phosphate from both si ... | 1989 | 2537209 |
| retrovirus protease characterized as a dimeric aspartic proteinase. | retroviruses and retroviruslike elements have a protease for specific cleavage of their polyprotein precursors. on the basis of amino acid sequences conserved among species and the sensitivity to protease inhibitors, it was proposed that the retrovirus protease could be classified as an aspartic proteinase. since the virus protease molecule is comparable to a single domain of aspartic proteinases having two symmetrical domains, we hypothesized and examined the dimer formation of the protease. th ... | 1989 | 2539514 |
| pathogenic effect of osteopetrosis virus strain mav-2(0) on guinea fowl pancreas. | osteopetrosis virus strain mav-2(0) in guinea fowl pancreas induces early unspecific changes in separate acini and the development of neoplasia among apparently unaffected acinar tissue. the tumors were classified as serous and mucinous adenomas and adenocarcinomas, as well as poorly differentiated carcinomas. foci of phenotypically altered acinar cells were observed in single experimental birds. | 1989 | 2545796 |
| secondary structural analysis of retrovirus integrase: characterization by circular dichroism and empirical prediction methods. | the retrovirus integrase (in) protein is essential for integration of viral dna into host dna. the secondary structure of the purified in protein from avian myeloblastosis virus was investigated by both circular dichroism (cd) spectroscopy and five empirical prediction methods. the secondary structures determined from the resolving of cd spectra through a least-squares curve fitting procedure were compared with those predicted from four statistical methods, e.g., the chou-fasman, garnier-osgutho ... | 1989 | 2546146 |
| continuous spectrophotometric assay for retroviral proteases of hiv-1 and amv. | ac-lys-ala-ser-gln-asn-phe(no2)-pro-val-val-nh2 (peptide i) and thr-phe-gln-ala-phe(no2)-pro-leu-arg-glu-ala (peptide ii) undergo hydrolysis between the p-nitrophenylalanyl and prolyl residues catalyzed by the proteases of hiv-1 and amv, respectively. the specific hydrolyses of peptides i and ii are accompanied by a decrease in their uv absorption at 269 nm (delta epsilon = 1000) and an increase at 316 nm (delta epsilon = 600). the use of microspectrophotometric cells allows continuous uv measur ... | 1989 | 2551268 |
| the avian retroviral integration protein cleaves the terminal sequences of linear viral dna at the in vivo sites of integration. | the purified integration protein (in) of avian myeloblastosis virus is shown to nick double-stranded oligodeoxynucleotide substrates that mimic the ends of the linear form of viral dna. in the presence of mg2+, nicks are created 2 nucleotides from the 3' oh ends of both the u5 plus strand and the u3 minus strand. similar cleavage is observed in the presence of mn2+ but only when the extent of the reaction is limited. neither the complementary strands nor sequences representing the termini of hum ... | 1989 | 2555556 |
| induction of nephroblastoma by myeloblastosis-associated virus type 1: state of proviral dnas in tumor cells. | myeloblastosis-associated virus type 1 (mav1) derived from a molecular clone of infectious proviral dna (b. perbal, j. s. lipsick, j. svoboda, r. f. silva, and m. a. baluda, j. virol. 56:240-244, 1985) was shown to specifically induce nephroblastoma in chickens and therefore belongs to the mav-n class. we show that nephroblastomas are polyclonal tumors containing rearranged proviral genomes. rearrangements occur preferentially in the gag-pol region of the mav1 proviral genome, and similar rearra ... | 1989 | 2564440 |
| rnase h-mediated release of the retrovirus rna polyadenylate tail during reverse transcription. | by examining enzymatic reactions in vitro, we found that an early event during reverse transcription of the avian myeloblastosis virus rna genome is the release of the 3' polyadenylate tail from the viral rna template. by using specially constructed molecules containing minus-strand, strong-stop dna and the 3' end of the viral rna genome, we found that the reverse transcriptase-associated rnase h is responsible for the endonucleolytic release of polyadenylate. | 1985 | 2578196 |
| inhibition of rna-directed dna polymerase from avian myeloblastosis virus by a 5-benzyl-6-aminouracil. | 5-(p-chlorobenzyl)-6-aminouracil (5-clau) inhibited rna-dependent dna polymerase (reverse transcriptase) from avian myeloblastosis virus. inhibition was expressed only in the presence of a polyribonucleotide template such as mrna or poly(ra), and kinetic analysis suggested that the action of 5-clau is competitive with template:primer. 5-clau did not inhibit hela dna polymerase gamma, an enzyme that efficiently copies polyribonucleotide templates. a mechanism is proposed in which a 5-clau:templat ... | 1985 | 2578788 |
| 2'-fluoro-2'-deoxycytidine triphosphate as a substrate for rna- and dna-dependent dna polymerases. | the ability of the analog 2'-fluoro-2'-deoxycytidine triphosphate (dcfltp) to be used as a substrate in the reactions catalyzed by xenopus laevis oocytes dna polymerase alpha and amv reverse transcriptase has been studied. the apparent km values for dctp and dcfltp, using activated dna as templates, were 0.6 microm and 7 mm with dna polymerase alpha and 0.14 microm and 7 microm with amv reverse transcriptase, respectively. as observed with dctp, aphidicolin was a noncompetitive inhibitor in the ... | 1985 | 2578819 |
| 2'-fluoro-2'-deoxypolynucleotides as templates and inhibitors for rna- and dna-dependent dna polymerases. | poly(2'-fluoro-2'-deoxyadenylic acid) (poly(dafl)) and poly(2'-deoxycytidylic acid) (poly(dcfl)) were tested as templates in dna synthesis reactions catalyzed by xenopus laevis oocytes dna polymerase alpha, mouse cell dna polymerase gamma and avian myeloblastis virus (amv) reverse transcriptase. poly(dafl).(dt)12 can fully substitute for poly(ra).(dt)12 as template with dna polymerase gamma, to 50% with reverse transcriptase, but was poorly recognized by dna polymerase alpha. dna synthesis by re ... | 1985 | 2578820 |
| effect of avian osteopetrosis virus infection on cells and their collagen synthesis in vitro. | primary avian tendon fibroblasts and calvarial osteoblasts were infected with the avian osteopetrosis virus mav.2-o, in vitro. the infected tendon cells could be cloned in soft agar and kept in culture for at least 25 passages, a number not reached by uncloned infected cells. in contrast to many other virus-transformed fibroblasts, these cells continued making collagen and fibronectin, and there were no gross morphological changes as observed in the light microscope. changes were seen in their c ... | 1985 | 2579813 |
| association of v-myc protein with chromatin. | the subnuclear distribution of proteins encoded by v-myb and v-myc was analysed in a cell-line of amv-transformed chicken myeloblasts superinfected by the myc-containing retrovirus mc29. p45v-myb and p110gag-myc, co-expressed in these cells, were released in similar fashion when nuclei were treated with salt or dnaase. analysis of nucleoprotein complexes extracted from nuclease-treated nuclei shows that p45v-myb and p110gag-myc are associated with a chromatin fraction of enhanced nuclease sensit ... | 1989 | 2644610 |
| purification and characterization of human immunodeficiency virus (hiv) core precursor (p55) expressed in saccharomyces cerevisiae. | the core structure of retroviruses, including the human immunodeficiency virus (hiv), consists of proteins that are initially synthesized as polyprotein precursors and then processed by a virally encoded protease yielding the mature core polypeptides. to obtain sufficient quantities of the purified hiv core precursor p55 for detailed studies, a segment of hiv dna encoding the full length core precursor polyprotein p55 was expressed in saccharomyces cerevisiae using a plasmid containing a constit ... | 1989 | 2663848 |
| identification of two translational products for c-myb. | the c-myb gene is the normal cellular homolog of v-myb, the oncogenic component of avian myeloblastosis virus (amv). the c-myb gene has previously been shown to code for a single protein species of about 75 kd. however, accumulating evidence indicates that this gene could code for multiple mrnas as a result of differential splicing. this was first detected in the abpl-2 tumor line and was later shown to occur in normal cells. to test if indeed these differentially spliced mrnas code for a new pr ... | 1989 | 2674850 |
| [synthesis of 2',3',-dideoxy-3'-fluoradenosine and -guanosine, their 5'-triphosphates and a study of 2',3'-dideoxy-3'-fluoronucleoside- 5'-triphosphates as substrates for dna-polymerases]. | potential antiviral and antitumour nucleosides, 3'-fluoro-2', 3'-dideoxy-adenosine and -guanosine, have been synthesized by the chemical transglycosylation reaction using 5'-o-acetyl-3'-fluoro-2', 3'-dideoxy-thymidine and -uridine as donors of the carbohydrate fragment and persilylated 6-n-benzoyladenine and 2-n-palmitoylguanine as acceptors, respectively. 5'-triphosphates of 3'-fluoro-2', 3'-dideoxy-thymidine, -cytidine, -adenosine, and -guanosine (dntp(3'f] were synthesized and tested as termi ... | 1989 | 2675851 |
| the v-myb oncogene product binds to and activates the promyelocyte-specific mim-1 gene. | the v-myb oncogene induces myeloid leukemias in chickens, transforms myeloid cells in vitro, and encodes a sequence-specific dna binding protein. we used differential hybridization to screen for v-myb-regulated genes in cells transformed by a temperature-sensitive mutant of the oncogene and identified a new gene, mim-1, which encodes a specifically expressed, secretable protein contained in the granules of both normal and v-myb-transformed promyelocytes. the promoter of the mim-1 gene contains t ... | 1989 | 2688896 |
| avian retroviral long terminal repeats bind ccaat/enhancer-binding protein. | dna-protein interactions involving enhancer and promoter sequences within the u3 regions of several avian retroviral long terminal repeats (ltrs) were studied by dnase i footprinting. the rat ccaat/enhancer-binding protein, c/ebp, bound to all four viral ltrs examined. the rous sarcoma virus binding site corresponded closely to the 5' limit of the ltr enhancer; nucleotides -225 to -188 were protected as a pair of adjacent binding domains. the fujinami sarcoma virus ltr bound c/ebp at a single si ... | 1989 | 2725492 |
| induction of leukemia by avian myeloblastosis virus: a mechanistic hypothesis. | 1989 | 2731435 | |
| protein encoded by v-erba functions as a thyroid-hormone receptor antagonist. | the thyroid-hormone receptor can, in the absence of its ligand, suppress activity of a responsive promoter. addition of thyroid hormone, however, results in the stimulation of expression. the oncogenic derivative of the thyroid-hormone receptor, v-erba, acts as a constitutive repressor and, when coexpressed with the receptor, blocks activation by thyroid hormone. thus, v-erba may be the first example of a dominant negative oncogene. | 1989 | 2733791 |
| biological properties of streptonigrin derivatives. iii. in vitro and in vivo antiviral and antitumor activities. | antitumor antibiotic streptonigrin (stn-cooh) is a potent inhibitor of avian myeloblastosis virus (amv) and human immunodeficiency virus reverse transcriptases. the carboxyl group at 2'-position of stn-cooh was modified to give esters, hydrazide, amides and amino acid derivatives for biological studies. against amv reverse transcriptase, the hydrazide, amides and amino acid derivatives showed inhibitory activity, which compared favorably to that of stn-cooh, with the id50 values ranging 2-8 micr ... | 1989 | 2737955 |
| preparation of soluble, biologically active alfalfa mosaic virus coat protein and its cacl2-induced degradation. | a method for the preparation of soluble protein from five biologically distinct alfalfa mosaic virus (amv) isolates is described. highly purified amv was dissociated with 1 m cacl2 in 10 mm sodium acetate, ph 6.0, and the precipitated rna was removed by centrifugation. the protein was dialysed against 10 mm sodium acetate, ph 6.0, containing 0.1 m cacl2. if the salt concentration was reduced further, proteins from some amv isolates precipitated. proteins prepared by this method were shown to be ... | 1989 | 2778029 |