Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| unequal human immunodeficiency virus type 1 reverse transcriptase error rates with rna and dna templates. | sequence variation in the type 1 human immunodeficiency virus (hiv-1) results, in part, from inaccurate replication by reverse transcriptase. although this enzyme is error-prone during synthesis in vitro with dna templates, the fidelity of rna-dependent dna synthesis relevant to minus-strand replication in the virus life cycle has not been examined extensively. in the present study, we have developed a system to determine the fidelity of transcription and reverse transcription and have used it t ... | 1992 | 1379727 |
| poly(a) rna in escherichia coli: nucleotide sequence at the junction of the lpp transcript and the polyadenylate moiety. | although it has been known for some time that bacterial mrna molecules carry polyadenylate moieties at their 3' ends, nothing is known about the molecular structure of bacterial poly(a) rna. to define the polyadenylylation site of a specific bacterial mrna, we took advantage of the presence of elevated levels of poly(a) rna in cells of escherichia coli deficient in exoribonucleases and synthesized dna complementary to polyadenylylated lipoprotein mrna, encoded by the lpp gene, by using avian mye ... | 1992 | 1380161 |
| exogenous primer-independent cdna synthesis with commercial reverse transcriptase preparations on plant virus rna templates. | upon reverse transcription and cloning manipulations with virion rnas of several plant viruses, namely beet yellows virus, brome mosaic virus, and potato virus x, we came across a significant background synthesis of cdna on the virion rna template in vitro independent of exogenous primers added. when tested with beet yellow virus rna template, several commercial preparations of avian myeloblastosis virus (amv) reverse transcriptase showed the background activity monitored by the [alpha-32p]dntp ... | 1992 | 1381874 |
| lobenzarit disodium (cca) inhibits the proliferation of human endothelial cells and the activity of dna polymerase alpha. | n-(2)-carboxyphenyl-4-chloroanthranilic acid disodium [lobenzarit disodium (cca)] is widely used for the treatment of patients with ra in japan; however, the pharmacological mechanism of the compound is still unclear. in this report, the effect of cca on the proliferation and dna synthesis of endothelial cells was examined. cca inhibited dna synthesis in endothelial cells at a rather lower concentration than that in fibroblasts and hela cells. the dna polymerase alpha activity was inhibited by c ... | 1992 | 1382382 |
| a comparison of the fidelity of copying 5-methylcytosine and cytosine at a defined dna template site. | 5-methylcytosine has been postulated to be an endogenous mutagen in procaryotes and eucaryotes leading to base substitution hot spots, c-->t transitions, resulting from spontaneous deamination of mc to t. the possibility remains, however, that a second mechanism involving mispairing of mc with a might also contribute to base substitution mutagenesis via g-->a transitions. stimulation of the g-->a mutational pathway could involve preferential misincorporation of damp opposite template mc compared ... | 1992 | 1383939 |
| cross-reacting and heterospecific monoclonal antibodies produced against arabis mosaic nepovirus. | monoclonal antibodies (mabs) were produced against arabis mosaic nepovirus (amv). a hybridoma screening procedure was applied which involved the testing of culture supernatants, before the hybridomas were cloned to single cell lines, for their reaction with eight nepoviruses [amv, cherry leafroll virus (clrv), grapevine fanleaf virus (gflv), peach rosette mosaic virus, raspberry ringspot virus (rrsv), tobacco ringspot virus, tomato black ring virus (tbrv) and tomato ringspot virus]. in addition ... | 1992 | 1402798 |
| protein truncation is not required for c-myb proto-oncogene activity in neuroretina cells. | the v-myb oncogene of avian myeloblastosis virus (amv) differs from its normal cellular counterpart by a truncation at both its amino and carboxyl termini and by a substitution of 11 amino acid residues. we had previously shown that v-myb-containing amv, in the presence of basic fibroblast growth factor, transformed chicken neuroretina (cnr) cells. to understand the mechanism of c-myb activation, we have tested whether avian retroviruses that express the full-length c-myb are also active on cnr ... | 1992 | 1404616 |
| 15gag proteinase of myeloblastosis-associated virus: specificity studies with substrate-based inhibitors. | the specificity of the proteinase of myeloblastosis-associated virus (mav) was studied with (a) 21 substrate-based inhibitors, (b) 9 inhibitors with pseudopalindrome sequences, (c) 8 chimeric inhibitors, and (d) 3 compounds designed as human immunodeficiency virus 1 (hiv-1) proteinase inhibitors. the central inhibitory unit (transition state or cleaved bond analog) and the role of the inhibitor side chains from p4 to p4' were investigated. mav proteinase prefers an aromatic side chain in p1 and ... | 1992 | 1417001 |
| [the technology for isolating the avian myeloblastosis virus in high titers from leukosis-free chicks]. | in order to enhance the outcome of high-quality reverse transcriptase enzyme, an efficient biotechnology was developed of accumulating and isolating the avian myeloblastosis virus (amv) in high titres from blood plasma of leukosis-free chickens. when commercial chickens are infected in most sensitive one-day age, the virus titre does not exceed the value of 10(12) particles per 1 ml of plasma. we used 3-4-day old leukosis free chickens and achieved a stable average titre of the virus of 5.10(12) ... | 1992 | 1430580 |
| cloning and nucleotide sequence of the 5' part of v-myb cdna. | cdna of a subgenomic v-myb mrna from amv-transformed bm-2 cells was cloned. sequencing of the 5' end of this cdna revealed the structure of both amv leader and the splice junction in v-myb message. the leader is a novel variant of known avian retrovirus leaders. the long open reading frame in the cloned cdna starts with six gag-derived codons spliced to the myb-specific sequence. | 1992 | 1519362 |
| identification of genes differentially expressed in two types of v-myb-transformed avian myelomonocytic cells. | in an earlier study we found that different forms of the v-myb oncogene transform myeloid cells which resemble either monoblasts [when v-myb of avian myeloblastosis virus (amv) was used] or promyelocytes [when a point mutant in v-myb of amv was used; introna, m., golay, j., frampton j., nakano, t., ness, s.a. & graf, t. (1990). cell, 63, 1287-1297]. in the present study we have searched for genes expressed in amv mutant-transformed promyelocytes that are not expressed in amv-transformed monoblas ... | 1992 | 1549365 |
| transforming potential of truncated v-myb and stimulation of replication by gag-myb fusion products. | we have previously reported that truncated forms of the v-myb oncogene of avian myeloblastosis virus (amv) are expressed in transformed chicken embryo fibroblasts (cef). in this paper, we show that deletion mutants encoding v-myb products altered in either the dna-binding or the negative regulatory domains are able to induce cef transformation. in addition, we report that recombinant plasmids expressing gag-myb fusion proteins are maintained as extrachromosomal forms in transfected cells. this o ... | 1992 | 1549366 |
| 1 alpha,25-dihydroxyvitamin d3 regulates the transcription of carbonic anhydrase ii mrna in avian myelomonocytes. | carbonic anhydrase ii (caii) is highly expressed in the osteoclast, where it is involved in the process of extracellular acidification required for bone resorption. we have previously shown that 1 alpha,25-dihydroxyvitamin d3 [1,25(oh)2d3], a steroid hormone that regulates the differentiation of macrophages and osteoclasts, induces the expression of caii mrna and protein in avian bone marrow cells. to determine whether this regulation occurred at the gene level, we have studied the effects of 1, ... | 1992 | 1584805 |
| mechanisms for the transformation of myeloid and erythroid cells by the nuclear oncogene v-myb. | 1992 | 1602808 | |
| extension of the dna binding consensus of the chicken c-myb and v-myb proteins. | the chicken c-myb gene and the v-myb oncogene transduced by avian myeloblastosis virus (amv) encode dna binding transcription activators. the dna binding domain of amv v-myb displays a number of amino acid changes relative to c-myb; v-myb proteins in which one or more of three crucial residues in the dna binding domain are mutated to resemble the c-myb sequence display altered transformation phenotypes. in order to establish whether the spectrum of dna binding sites which amv v-myb can recognise ... | 1992 | 1620600 |
| production of v-myb and c-myb in insect cells infected with recombinant baculoviruses. | recombinant baculoviruses expressing the v-myb and c-myb genes in infected insect cells were constructed. the electrophoretic mobilities of their immunoreactive products were the same as those of the authentic myb proteins from chicken cells. the system provides a convenient source of relatively large amounts of v-myb or c-myb for in vitro binding studies. | 1992 | 1639269 |
| a covalent complex between retroviral integrase and nicked substrate dna. | purified retroviral integrase (in) from avian sarcoma-leukosis viruses can appropriately process the termini of linear viral dna, cleave host dna in a sequence-independent manner, and catalyze integrative recombination; an exogenous source of energy is not required for these reactions. using dna substrates containing radioactive phosphate groups, we demonstrate that in becomes covalently joined to the new 5' phosphate ends of dna produced at sites of cleavage. most of the phosphodiester linkages ... | 1991 | 1647013 |
| cdna cloning of a homeobox-containing gene expressed in avian myeloblastic virus-transformed chicken monoblastic leukaemia cells. | by combining the polymerase chain reaction and differential library screening, a cdna for an mrna expressed in chicken avian myeloblastosis virus (amv)-transformed monoblasts was isolated. this mrna is not expressed in erythroblast or t-lymphoblast cell lines. induced differentiation of the cells of the amv-transformed bm2 line was associated with reduced levels of this transcript. the predicted protein product of chox m was a homeodomain factor similar to murine hox-4.3. | 1991 | 1674560 |
| relationship of 2',3'-cyclic nucleotide 3'-phosphohydrolase activity of large enveloped rna viruses to host cell activity. | purified virions of the large rna viruses show 2',3'-cyclic nucleotide 3'-phosphohydrolase (3'-cnpase) activity. the 3'-cnpase activity is virion-associated and stimulated by their treatment with nonionic detergents. cytopathic viruses such as influenza a2 (singapore/57), ndv, and vsv showed the specific activity of a virion-associated 3'-cnpase equal to or lower than the specific activity of host cell enzyme. retroviruses are an example of extreme relationship of 3'-cnpase to virion. with the a ... | 1991 | 1688073 |
| specificities involved in the initiation of retroviral plus-strand dna. | reverse transcription of the retroviral rna genome begins with trna-primed synthesis of a minus-strand dna, which subsequently acts as the template for the synthesis of plus-strand dna. this plus-strand dna is initiated at a unique location and makes use of a purine-rich rna oligonucleotide derived by rnase h action on the viral rna. to determine the variables that are relevant to successful specific initiation of plus-strand dna synthesis, we have used nucleic acid sequences from the genome of ... | 1990 | 1688626 |
| base mispair extension kinetics. comparison of dna polymerase alpha and reverse transcriptase. | a polyacrylamide gel assay is used to measure the kinetics of adding a single deoxyribonucleotide onto either a correctly matched or mismatched primer 3' terminus (on m13 template) for all possible dna base pairs and mispairs using drosophila melanogaster dna polymerase alpha (pol alpha) and avian myeloblastosis virus reverse transcriptase. the reverse transcriptase catalyzes chain extension from transition mispairs (pur.pyr and pyr.pur, where pur is purine and pyr is pyrimidine) more efficientl ... | 1990 | 1688852 |
| potent dna chain termination activity and selective inhibition of human immunodeficiency virus reverse transcriptase by 2',3'-dideoxyuridine-5'-triphosphate. | 2',3'-dideoxyuridine (ddurd) exhibits poor if any anti-human immunodeficiency virus (hiv) activity in ath8 and mt-4 cells. this is in agreement with the failure of ddurd to be efficiently anabolized intracellularly to its 5'-triphosphate metabolite. however, 2',3'-dideoxyuridine-5'-triphosphate (ddutp) proved to be a potent and selective inhibitor of the reverse transcriptase of hiv (ki, 0.05 microm) and avian myeloblastosis virus (ki, 1.0 microm). bacterial dna polymerase i, mammalian dna polym ... | 1990 | 1689452 |
| improved assays for dna-polymerizing enzymes by the use of enzymatically synthesized 5-[125i]iodo-2'-deoxyuridine triphosphate, illustrated by direct quantitation of anti-hiv reverse transcriptase antibody and by serum dna polymerase analyses. | a one-step procedure which uses enzymes in a crude extract of herpes simplex virus (hsv) type 1-infected cells to synthesize 5-[125i]iodo-2'-deoxyuridine triphosphate [( 125i]dutp) from [125i]du is described. the design of a one-step procedure for the purification of the product is also presented. the recovery of [125i]dutp from [125i]du varied between 50 and 75%, the radiochemical purity of the product was greater than 90%, and both synthesis and purification were completed within 8 h. the sens ... | 1990 | 1690011 |
| reverse transcriptases and genomic variability: the accuracy of dna replication is enzyme specific and sequence dependent. | kinetics of incorporation of correct and incorrect deoxynucleotides by three reverse transcriptases have been followed, by gel assay, on a series of dna templates, including part of the hiv-1 gag dna minus strand. insertion kinetics for the properly matched nucleotide at a given place on the template vary strongly from one enzyme to the next. no significant correlation is found between the site-specific michaelis constants, while the maximal velocities are more closely connected. for a given rev ... | 1990 | 1691709 |
| [rna-dependent dna-polymerase from avian myeloblastosis virus: effectiveness of interaction with oligothymidylate primers of various length]. | optimal conditions for the reaction of polymerization catalyzed by rna-dependent dna-polymerase from amv on poly(a)- and poly(da)-templates with d(pt)n-primers were established. optimal concentrations of the components and ph of the reaction mixtures were found out to differ significantly. dttp was shown to be both a nucleotide substrate and a minimal primer of the polymerization. the km values for d(pt)2-primer (km = 0.11 mm and 0.54 for poly(a) and poly(da)-templates, respectively) and longer ... | 1990 | 1694567 |
| selective action of 3'-azido-3'-deoxythymidine 5'-triphosphate on viral reverse transcriptases and human dna polymerases. | the action of 3'-azido-3'-deoxythymidine 5'-triphosphate (n3dttp) on dna strand elongation catalyzed by human immunodeficiency virus type 1 reverse transcriptase was evaluated in comparison with human dna polymerase alpha and proliferating cell nuclear antigen-independent dna polymerase delta. sequencing gel analysis demonstrated that the human immunodeficiency virus 1 reverse transcriptase preferentially incorporated n3dttp into the t sites of the growing dna strands and caused chain terminatio ... | 1990 | 1694849 |
| inhibition of human immunodeficiency virus-1 reverse transcriptase activity by rubromycins: competitive interaction at the template.primer site. | rubromycins, a class of quinone antibacterials, were discovered to selectively inhibit human immunodeficiency virus-1 (hiv-1) rna-directed dna polymerase (reverse transcriptase) (rt) activity more potently than cellular dna polymerase alpha. beta- and gamma-rubromycin each inhibited equipotently hiv-1 rt and avian myeloblastosis virus rt, in a concentration-dependent manner, and were significantly weaker as inhibitors of calf thymus dna polymerase alpha. these agents inhibited hiv-1 rt reversibl ... | 1990 | 1695317 |
| [comparative inhibitory analysis of dna biosynthesis catalyzed by retrovirus reverse transcriptase]. | comparative study of dna biosynthesis inhibition, catalyzed by avian myeloblastose virus (amv) reverse transcriptase (rt), human immunodeficiency virus (hiv) recombinant and native rt, has been performed. 3'-azido-2',3'-dideoxythymidine 5'-triphosphate (azttp); 3'-azido-2',3'-dideoxythymidine 5'-methylenephosphonate-diphosphate: 3'-azido-2',3'-dideoxythymidine 5'-phosphate-phosponoacetate; 3'-azido-2',3'-dideoxythymidine 5'-phosphate-dibromomethylenephosphonate; 2',3'-o-isopropylidenecytidine 5' ... | 1990 | 1695849 |
| z-dna affinity chromatography. | in this chapter we have detailed a method that can be generalized to link virtually any dna substrate to a chromatography matrix at its ends via an avidin-biotin linkage. we have used this technique to construct a left-handed z-dna column for the purpose of identification and purification of z-dna-binding proteins. this technique for the linkage of dna to a column matrix by avidin-biotin technology can be modified, however, to produce linked multimeric sequences specific for regulatory or other ... | 1990 | 1697020 |
| hybrids between rubella virus and a latent virus of baby hamster kidney cell line bhk21: characterization of rubella virus and type 2 hybrid virus genomes and determination of their physical homology. | the biochemical nature of rubella virus and type 2 hybrid virus, which is a recombinant between rubella virus and a latent retrovirus of bhk21 cells, has been characterized. type 2 hybrid virus carries dna polymerase able to copy exogenous dna. however, disrupted type 2 hybrid virions do not synthesize detectable amounts of dna using the endogenous viral rna or synthetic poly(ra)/oligo(dt) primed as a template. thus, the type 2 hybrid virus dna polymerase has no detectable reverse transcriptase ... | 1990 | 1697423 |
| synthesis of dna by human immunodeficiency virus reverse transcriptase is preferentially blocked at template oligo(deoxyadenosine) tracts. | the genome of human immunodeficiency virus (hiv) and especially the envelope gene are mutated with unusually high frequency during in vivo replication. recent studies indicate that hiv reverse transcriptase (rt) is unusually error prone and that the number of generated mutations is disproportionately high within repetitive base sequences. to study the ability of recombinant and wild-type hiv rt to traverse specific homo-oligomeric stretches, we used bacteriophage m13 dna templates that contain d ... | 1990 | 1698789 |
| inhibition of avian myeloblastosis virus reverse transcriptase by diphosphates of acyclic phosphonylmethyl nucleotide analogues. | diphosphates of n-(2-phosphonylmethoxyethyl) derivatives of heterocyclic bases were studied in the endogenous oligo(dt)12-18 primed reaction of reverse transcriptase from detergent-disrupted amv(mav) retrovirions. these diphosphates (analogues of nucleotide 5'-triphosphates) exhibited an inhibitory activity towards reverse transcriptase. this inhibitory activity was dependent on the character of the heterocyclic base and decreased in the order: 2-aminoadenine greater than adenine greater than gu ... | 1990 | 1699492 |
| acyclic nucleotide analogues: synthesis, antiviral activity and inhibitory effects on some cellular and virus-encoded enzymes in vitro. | several n-(s)-(3-hydroxy-2-phosphonylmethoxypropyl) (hpmp) and n-(2-phosphonylmethoxyethyl) (pme) derivatives of purine bases (adenine, guanine, 2-aminoadenine, 3-deazaadenine) and cytosine inhibit the growth of various dna viruses. pme-derivatives (pmea, pmeg and pmedap) are also active against retroviruses. both types of nucleotide analogues undergo phosphorylation by cellular nucleotide kinases to their mono- and diphosphates. the phosphorylation with crude extracts of l-1210 cells is potenti ... | 1990 | 1699493 |
| an improved method for sequencing of rna templates. | 1990 | 1700370 | |
| a monoclonal antibody that neutralizes epstein-barr virus, human cytomegalovirus, human herpesvirus 6, and bacteriophage t4 dna polymerases. | a monoclonal antibody (mab) designated 55h3 was produced by using chemically induced epstein-barr virus genome-positive b95-8 cells. mab 55h3, which reacted with an 85- to 80-kda polypeptide, neutralized epstein-barr virus-encoded dna polymerase activity in crude extracts of chemically induced m-aba, hr-1, and b95-8 cells, as well as the partially purified epstein-barr virus dna polymerase in a dose-dependent manner. the mab also neutralized the virus-encoded dna polymerase activity from cells i ... | 1990 | 1700422 |
| ribavirin is an inhibitor of human immunodeficiency virus reverse transcriptase. | ribavirin inhibits the human immunodeficiency virus reverse transcriptase in an in vitro reaction. ribavirin-5'-diphosphate was close to 40% more inhibitory than ribavirin-5'-triphosphate. unphosphorylated ribavirin had a reduced, but detectable, effect as an inhibitor, compared with the phosphorylated forms. the compounds seem to have a direct effect on the viral polymerase, and no chain termination was observed in the presence of ribavirin-5'-triphosphate. combination of any of the ribavirin d ... | 1990 | 1701213 |
| [fluorescent analogs of nucleoside-5'-phosphates for the study of nucleic acids by nonradioactive methods]. | the synthesis of 2'-deoxyuridine 5'-triphosphate analogues with fluorescent residues of fluorescein and rhodamine nature at c5 of the uracil base was performed. reverse transcriptase of avian myeloblastosis virus, dna polymerase beta of rat liver, terminal deoxynucleotidyl transferase of calf thymus and e. coli dna polymerase i, klenow fragment, were shown to be capable to incorporate a nucleotide residue with fluorescent label into 3'-terminus of oligonucleotide. these fluorescent labeled oligo ... | 1990 | 1701217 |
| [the effect of bases noncomplementary to the template on the effectiveness of interaction between primers and avian myeloblastosis virus reverse transcriptase]. | the comparison of the km and vmax values for various primers was carried out. the primers were either completely complementary to the poly(a)-template or contained noncomplementary bases in different positions from the 3'-end. an increase of the km and vmax values for primers containing noncomplementary bases was shown. the affinity of the amv-revertase complex with poly(a)-template to d(pt)10 was shown to be higher by a factor of 93, 325, 338, 425, 95 and 15 than to d(pt)9(pc), d[(pt)2pc]3pt, d ... | 1990 | 1701218 |
| a comparison of the initiating abilities of ribo- and deoxyriboprimers in dna polymerization catalyzed by amv reverse transcriptase. | the difference in optimal conditions for dna polymerization catalyzed by amv reverse transcriptase on poly(a) and poly(da) templates with d(pt)10 and (pu)10 primers has been found. a comparison of the initiating abilities of d(pt)10 and (pu)10 primers under optimal conditions for various template.primer complexes has been made. the best template.primer complex was poly(a).d(pt)10 and the worst was poly(a).(pu)10. the lengthening of d(pt)n primers by a mononucleotide unit (n = 2-10) increases the ... | 1990 | 1701399 |
| blockage of amv reverse transcriptase by antisense oligodeoxynucleotides. | synthetic oligodeoxynucleotides, either unmodified or linked to an intercalating agent, have been used to prevent cdna elongation by the amv reverse transcriptase. oligonucleotide/rna hybrids specifically arrest primer extension. the blockage involves the degradation of the rna part bound to the antisense oligonucleotide by the rnase-h activity associated with the retroviral polymerase. | 1990 | 1701402 |
| reverse transcription and cdna amplification by the polymerase chain reaction of equine arteritis virus (eav). | a technique is described for the amplification and specific identification of equine arteritis virus (eav) nucleotide sequences. the polymerase chain reaction (pcr) was evaluated initially by amplification of cloned virus specific cdna sequences prior to amplification of single-stranded (ss) cdna produced by reverse transcription (rt) of viral genomic rna. three separate primer pairs were used for rt/pcr of eav genomic rna, each pair producing only one band in agarose gels of the predicted size ... | 1990 | 1702094 |
| mechanism of tumor cell killing by ho-221, a novel antitumor compound. | the mechanism of tumor cell killing by ho-221, a novel benzoylphenylurea derivative that shows broad-spectrum antitumor activities, was studied. ho-221 strongly inhibited the activity of mammalian dna polymerase alpha but not that of dna polymerases beta or gamma. the inhibition was equivalent to that induced by aphidicolin and ara-ctp, which were selective inhibitors of the enzyme. furthermore, the inhibition by ho-221 of dna polymerase alpha was found to be non-competitive with respect to dctp ... | 1990 | 1702366 |
| effects of 2-chloro-2'-deoxyadenosine 5'-triphosphate on dna synthesis in vitro by purified bacterial and viral dna polymerases. | 2-chloro-2'-deoxyadenosine 5'-triphosphate (cldatp) was compared with datp as a substrate for dna synthesis by bacterial and viral dna polymerases in vitro. lengths of chain extension and dna synthesis pause sites were determined by comparison with products generated by dideoxynucleotide sequencing methods on the same end-labeled primer/template duplex after high-resolution polyacrylamide gel electrophoresis. reverse transcriptase (rt) from human immunodeficiency virus (hiv-1) and avian myelobla ... | 1991 | 1703019 |
| avian myeloblastosis virus reverse transcriptase. effect of glycerol on its hydrodynamic properties. | although reverse transcriptase has been the subject of intensive investigation, minimal information is available regarding the physical properties of the enzyme. the basic hydrodynamic properties of avian myeloblastosis virus reverse transcriptase in solution were measured by both sedimentation velocity and equilibrium measurements in two buffer systems. in a 0.3 m potassium phosphate buffer system, ph 7.8, the enzyme sedimented as a homogenous particle with a sedimentation coefficient of (7.1 + ... | 1991 | 1703151 |
| inhibition of avian myeloblastosis virus reverse transcriptase activity by hoe/bay 946, a polysulphated polysaccharide. | 1990 | 1703305 | |
| inhibition of avian myeloblastosis virus reverse transcriptase by aurochloric acid. | we investigated the inhibitory effects of aurochloric acid (aucl4h) on reverse transcriptase (rt) derived from avian myeloblastosis virus and dna polymerase alpha (pol. alpha) purified from hela s3 cells. the activities of rt, pol. alpha and e. coli dna polymerase i (pol. i) with dttp as the substrate were inhibited 50% at aucl4h concentrations of 18 microm, 43 microm and 230 microm, respectively. aucl4h inhibited rt activity competitively with respect to the substrate, dttp, and uncompetitively ... | 1990 | 1703521 |
| 5'-derivatives of oligonucleotides as primers of dna polymerization catalyzed by amv reverse transcriptase and klenow fragment of dna polymerase 1. | the km and vmax values for d(pt)8 and its derivatives containing various 5'-end groups were estimated in the reaction of polymerization catalyzed with amv-rt and fk. the change in affinity of modified primers was more pronounced in the case of amv-rt than in the case of fk. introducing in d(pt)8 of intercalators such as phenazinium, ethidium and daunomycin residues results in 2.7-, 8.7- and 11-fold increases in the primer affinity to amv-rt, respectively. however, in the case of hemin and choles ... | 1991 | 1707828 |
| polymerization and rnase h activities of the reverse transcriptases from avian myeloblastosis, human immunodeficiency, and moloney murine leukemia viruses are functionally uncoupled. | the functional interaction between the rna-dependent dna polymerase and the rnase h activities of reverse transcriptases (rts) were examined using a 272 nucleotide long plasmid-derived rna transcript primed in a specific location. properties of the avian myeloblastosis virus (amv) rt, the human immunodeficiency virus rt and the moloney murine leukemia virus rt were examined. all three enzymes formed stable complexes with the primer-template with half-lives ranging from about 16 to 41 s. each enz ... | 1991 | 1708386 |
| saponins from leaves of acanthopanax hypoleucus makino. | from the leaves of acanthopanax hypoleucus makino (araliaceae), five triterpenoidal saponins, having oleanolic acid and hederagenin as sapogenins, were isolated. on the basis of chemical and spectral data, the structures of two new saponins, named hypoleucosides a (1), and b (5) were elucidated as follows: 1; 3-o-beta-d-glucopyranosyl 11 alpha-methoxy-oleanolic acid 28-o-beta-d-glucopyranosyl ester, 5; 3-o-beta-d-glucopyranosyl-(1----2)-alpha-l-arabinopyranosyl-(1---- 4)-beta-d-glucopyranosyl ol ... | 1990 | 1709393 |
| rapid detection of bovine viral diarrhea virus by polymerase chain reaction. | the polymerase chain reaction was used to detect genomic sequences of the positive-stranded rna of bovine viral diarrhea virus (bvdv), a member of the family togaviridae. using a set of 20-bp primers located within the conserved 3' region of the bvdv genome, we were able to consistently amplify a 205-bp target sequence from bvdv cdna. bvdv rnas from cell culture-propagated bvdv reference strains, diverse unrelated cytopathic and noncytopathic field isolates, and clinical serum samples were trans ... | 1991 | 1709950 |
| evaluation of natural products as inhibitors of human immunodeficiency virus type 1 (hiv-1) reverse transcriptase. | inhibition of human immunodeficiency virus reverse transcriptase is currently considered a useful approach in the prophylaxis and intervention of acquired immunodeficiency syndrome (aids), and natural products have not been extensively explored as inhibitors of this enzyme. we currently report that the reverse transcriptase assay developed for the detection of the enzyme in virions involving polyadenylic acid.oligodeoxythymidylic acid (poly ra.oligo dt) and radiolabeled thymidine 5'-triphosphate ... | 1991 | 1710653 |
| 9-[(2rs)-3-fluoro-2-phosphonylmethoxypropyl] derivatives of purines: a class of highly selective antiretroviral agents in vitro and in vivo. | a new class of compounds, 9-[(2rs)-3-fluoro-2-phosphonylmethoxypropyl] [(rs)-fpmp] derivatives of purines, is described that has selective activity against a broad spectrum of retroviruses [including human immunodeficiency virus type 1 (hiv-1) and type 2 (hiv-2)] but not other rna or dna viruses. this activity spectrum is completely different from that of the parental compounds, 9-[(2s)-3-hydroxy-2-phosphonylmethoxypropyl] [(s)-hpmp] derivatives of purines, which are active against a broad range ... | 1991 | 1711214 |
| photoaffinity labeling of the primer binding domain in murine leukemia virus reverse transcriptase. | we have labeled the primer binding domain of murine leukemia virus reverse transcriptase (mulv rt) by covalently cross-linking 5' end labeled d(t)8 to mulv rt, using ultraviolet light energy. the specificity and the functional significance of the primer cross-linking reaction were demonstrated by the fact that (i) other oligomeric primers, trnas, and also template-primers readily compete with radiolabeled d(t)8 for the cross-linking reaction, (ii) under similar conditions, the competing primers ... | 1991 | 1711370 |
| requirements for the catalysis of strand transfer synthesis by retroviral dna polymerases. | we have examined the properties of reverse transcriptases (rts) required for strand transfer synthesis on poly(ra). in this process, a primer is elongated on one template and then switches to other templates for additional elongation until it is much longer than the templates on which it was made. models of retrovirus replication require the rt to catalyze two distinct strand transfers. additionally, they propose that the rt ribonuclease h (rnase h) activity is involved in both transfers. rts fr ... | 1991 | 1712774 |
| human immunodeficiency virus reverse transcriptase ribonuclease h: specificity of trna(lys3)-primer excision. | two model substrates were prepared to examine the mechanism of trna-primer excision catalyzed by reverse transcriptase associated ribonuclease h (rt-rnase h). the first model substrate contained sequences from the hiv genome and was designed to be structurally similar to the dna-extended trna created by initiation of minus-strand dna synthesis during retroviral replication. the dna-extended rna was a template and was annealed to a dna oligonucleotide that primed reverse transcription of the rna ... | 1991 | 1713059 |
| detection of hantavirus rna in tissues of experimentally infected mice using reverse transcriptase-directed polymerase chain reaction. | detection of hantaviruses, the etiological agents of hemorrhagic fever with renal syndrome (hfrs), by virus isolation using experimental animals or cell culture is time-consuming. a more rapid but equally specific method is needed. we used a reverse transcriptase-directed polymerase chain reaction (rt-pcr) to detect hantavirus genomic sequences and compared its sensitivity with conventional virus isolation. rna, extracted by the guanidinium isothiocyanate-cesium chloride method from hantavirus-i ... | 1991 | 1713266 |
| [3'-mercapto-3'-deoxythymidine-5'-triphosphate as a terminator of dna synthesis catalyzed by rna-dependent dna-polymerases]. | 3'-mercapto-3'-deoxy-ttp was synthesized and tested as dna chain terminator nucleotide for calf thymus alpha dna polymerase, e. coli dna polymerase i (klenow fragment), terminal deoxyribonucleotidyltransferase (bollum enzyme) and reverse transcriptase from amv- and hiv-i-viruses. it was shown that the compound terminates dna chain elongation by reverse transcriptases selectively and irreversibly. other tested dna polymerases do not use this nucleotide analogue as a substrate. 3'-mercapto-3'-deox ... | 1991 | 1716104 |
| inhibition of avian myeloblastosis virus reverse transcriptase by heterocyclic quinones: structure-activity correlation. | synthetic heterocyclic quinones (107 samples) consisting of o- and p-quinoline quinones, o-isoquinoline quinones and p-quinoxaline quinones as well as o- and p-naphthoquinones (3 samples) were tested for their inhibitory activities against avian myeloblastosis virus reverse transcriptase (amv-rt) and cytotoxic activities against mouse lymphoblastoma l5178y cells. in general, o-quinoline quinones (i.e., the 5,6-quinolinedione derivatives) are more potent inhibitors of amv-rt than p-quinoline quin ... | 1991 | 1716528 |
| podoscyphic acid, a new inhibitor of avian myeloblastosis virus and moloney murine leukemia virus reverse transcriptase from a podoscypha species. | a novel enzyme inhibitor of rna-directed dna-polymerases of avian myeloblastosis and murine leukemia virus was isolated from fermentations of an tasmanian podoscypha species. its structure was elucidated by spectroscopic methods and oxidative degradation as (e)-4,5-dioxo-2-hexadecenoic acid (1). the enzyme inhibitor, which was named podoscyphic acid, did not inhibit dna and rna synthesis in permeabilized l 1210 cells nor did it affect rna synthesis in isolated nuclei of l 1210 cells. 1 inhibits ... | 1991 | 1716894 |
| immunohistochemical evaluation of reverse transcriptase in breast carcinoma with polyclonal antibodies raised in rabbit. | in this study, the presence of reverse transcriptase in breast tumours was examined with immunoperoxidase staining using antibodies raised in rabbit against reverse transcriptase of moloney murine leukemia virus and against reverse transcriptase of avian myeloblastosis virus. the specificity of such antibodies was investigated with elisa and western blotting techniques. five cases of infiltrating ductal carcinomas were found positive with the immune serum anti-reverse transcriptase of moloney mu ... | 1990 | 1717028 |
| purification and partial characterization of equine infectious anemia virus reverse transcriptase. | previously we raised a rabbit monospecific antibody (c2003) against a synthetic peptide derived from a sequence within the c-terminal portion of the reverse transcriptase (rt) of the human immunodeficiency virus type 1 (hiv-1). this sequence is found to be conserved in the predicted amino acid sequence of a related lentivirus, the equine infectious anemia virus (eiav). it was previously determined that the c2003 antibody could cross-react with native eiav rt and directly inhibit the dna polymera ... | 1991 | 1718086 |
| reverse transcriptase from human immunodeficiency virus: a single template-primer binding site serves two physically separable catalytic functions. | the binding of substrates to recombinant reverse transcriptase from human immunodeficiency virus (hiv) and the natural enzyme from avian myeloblastosis virus (amv) has been examined by analyzing both the ribonuclease h and the rna-dependent dna polymerase activities. with 3'-end-labeled globin mrna hybridized to (dt)15 as the substrate in the ribonuclease h reaction, the enzymes partially deadenylated the mrna in a distributive manner. under these conditions, there was a rapid initial burst foll ... | 1991 | 1718423 |
| effect of glutaraldehyde-fixation on the immunogenicity, particle stability and antigenic reactivity of alfalfa mosaic virus, and the specificity of elicited antibodies. | glutaraldehyde-fixation was shown to stabilize the structural integrity of alfalfa mosaic virus (amv) particles as well as to increase their immunogenicity and antigenic reactivity. the antigenic reactivity of the particles was substantially increased irrespective of whether the antibodies were from animals immunized with native or fixed amv, or preparations of coat protein subunits isolated from the virus. no significant changes in the antigenic specificity of amv particles were detected follow ... | 1991 | 1719013 |
| psychotrine and its o-methyl ether are selective inhibitors of human immunodeficiency virus-1 reverse transcriptase. | psychotrine dihydrogen oxalate and o-methylpsychotrine sulfate heptahydrate (mp), the salts of isoquinoline alkaloids from ipecac, were found to be potent inhibitors of the dna polymerase activity of human immunodeficiency virus-1 reverse transcriptase (hiv-1 rt). we currently report the results of additional studies designed to characterize the mechanism of inhibition facilitated by mp. the inhibition was noncompetitive with respect to ttp and uncompetitive with respect to poly(ra) and oligo(dt ... | 1991 | 1721050 |
| avian myeloblastosis virus reverse transcriptase inhibition by nalidixic acid. | nalidixic acid, a very specific inhibitor of bacterial dna synthesis, has been studied for its action on the avian myeloblastosis virus reverse transcriptase activity. the drug inhibited the dna synthesis reaction catalyzed by the viral enzyme in the presence of different template-primers. the inhibitory effect by nalidixic acid was higher with polyriboadenylic acid than with polyribocytidylic acid as a synthetic template. with activated dna as a template nalidixic acid preferentially inhibited ... | 1991 | 1723488 |
| [formation of phosphonoester bonds, catalyzed by dna polymerases]. | 3'-fluoro-2',3'-dideoxythymidine 5'-(alpha-methylphosphonyl)-beta, gamma-diphosphate (i) and 2'-deoxythymidine 5'-(alpha-methylphosphonyl)-beta,gamma-diphosphate (ii) were synthesised. reverse transcriptases of hiv and avian myeloblastosis virus, rat liver dna polymerase beta, calf thymus terminal deoxynucleotidyl transferase and e. coli dna polymerase i kf incorporated both compounds into the growing dna chain, kf being the least effective. compound i revealed termination substrate properties, ... | 1991 | 1726022 |
| inhibition of reverse transcription by unmodified and modified antisense oligodeoxynucleotides. | we used oligodeoxynucleotides to prevent reverse transcription of beta-globin mrna by reverse transcriptase of avian myeloblastosis virus. unmodified oligomers hybridized to the template arrested synthesis of cdna in a dose dependent manner. the longer the oligomer the more efficient the inhibition, 50% inhibition being achieved at 0.3 and 30 microm of a 17- or a 12-mer, respectively. the use of complementary oligonucleotides with a 3' end blocked either by a dideoxy residue or by a dodecanol gr ... | 1991 | 1726738 |
| hexopyranosylnucleoside 6'-triphosphates are not substrates for dna polymerases. | 1991 | 1726740 | |
| oligonucleotides and their derivatives as tools for investigations of protein-nucleic acid interactions in template biocatalysis. | on the basis of quantitative characteristics (kd, km, gibbs energy values) for the interaction of oligonucleotides with template and primer site of eucaryotic and procaryotic dna polymerases, a general model of template-primer interaction with these enzymes was suggested. the interactions of amv- and hiv- reverse transcriptases with various 5'-derived oligonucleotides and with human dna polymerase alpha and klenow fragment are compared. the results obtained suggest a method to improve selectivel ... | 1991 | 1726742 |
| nucleoside 5'-(alpha-methylphosphonyl)-beta, gamma-diphosphates as substrates for dna polymerases. | 1991 | 1726745 | |
| definition of functional domains in p135gag-myb-ets and p48v-myb proteins required to maintain the response of neuroretina cells to basic fibroblast growth factor. | the v-myb- and v-ets-containing e26 retrovirus induces the proliferation of chicken neuroretina (cnr) cells in minimal medium. proliferation of e26 cnr cells is strongly stimulated by basic fibroblast growth factor (bfgf). the v-myb-containing avian myeloblastosis virus also induces the proliferation of infected cnr cells stimulated by bfgf. both e26 cnr and avian myeloblastosis virus cnr cells are able to form colonies in soft agar in the presence of bfgf. this suggests that the v-myb product, ... | 1992 | 1727478 |
| isolation, biochemical characterization and crystallization of the p15gag proteinase of myeloblastosis associated virus expressed in e. coli. | 1. the p15gag proteinase responsible for the processing of the polyprotein precursor of the myeloblastosis associated virus was obtained by a recombinant technique in an e. coli expression system. the massive expression of the intentionally truncated precursor (pr25lac-delta gag) was accompanied by its structurally correct processing. 2. three procedures for the purification of the recombinant proteinase from both the cytoplasmic fraction and the inclusion bodies were developed. 3. the purified ... | 1992 | 1733789 |
| change in phenotype and encapsidated rna segments of an isolate of alfalfa mosaic virus: an influence of host passage. | a local lesion isolate of alfalfa mosaic virus (amv-n20) from lucerne was found to encapsidate two extra rnas in addition to the four major rnas (rna1, -2, -3 and -4). these were resolved by gel electrophoresis both under native conditions and after glyoxal denaturation. the rna with an electrophoretic mobility between that of rnas 2 and 3 was designated rna31, that between rnas 3 and 4 was designated rna3s. sucrose density gradient centrifugation analysis of amv-n20 showed six instead of the no ... | 1991 | 1765766 |
| protein-engineered proteinase of myeloblastosis associated virus, an enzyme of high activity and hiv-1 proteinase-like specificity. | 1991 | 1812751 | |
| p15gag proteinase of myeloblastosis associated virus: specificity studies with substrate based inhibitors. | 1991 | 1812752 | |
| rapid detection of hog cholera virus in tissues by the polymerase chain reaction. | a rapid method for the detection of hog cholera virus (hcv) in infected tissues, using polymerase chain reaction (pcr) was developed. total rna isolated from hcv-infected tissues was reverse transcribed with amv reverse transcriptase and the resulting complementary dna was amplified by taq dna polymerase in the presence of two hcv-specific primers. the amplified dna fragment was detected by agarose gel electrophoresis. the sensitivity of this method was at 10(4) tcid50 of hcv. the sensitivity in ... | 1991 | 1816255 |
| defining nucleic acid-binding properties of avian retrovirus integrase by deletion analysis. | integration of retroviral dna into the host genome requires the activity of retrovirus-encoded integration protein in. we expressed rous sarcoma virus (rsv) in, 286 amino acid residues in length, by using in vitro transcription, followed by in vitro translation in rabbit reticulocyte lysate. the nucleic acid-binding activity of in vitro-translated in was assessed by using dna-cellulose affinity chromatography and poly(u)-sepharose affinity chromatography and by sedimentation analysis in the pres ... | 1991 | 1847445 |
| specificity studies on retroviral proteinase from myeloblastosis-associated virus. | the specificity of the p15 proteinase of myeloblastosis-associated virus (mav) was tested with nonviral high molecular weight substrates and with synthetic peptides. peptides with sequences spanning known cleavage sites in viral polyproteins of rous sarcoma virus (rsv) and avian leukemia viruses, as well as in bsa and hsa, were synthesized, and the rate of their cleavage by the mav proteinase was compared. synthetic peptides require for successful cleavage at least 4 residues at the n-terminal s ... | 1991 | 1849425 |
| proto-oncogene expression in avian hematopoietic tissues. | previous findings from this laboratory (kim & baluda, 1988) have shown that the proto-oncogenes ets, fps, mht (raf), myc and rel are expressed in avian myeloblastosis virus (amv)-transformed cells, whereas the myb gene is repressed. in this study five different chicken hematopoietic tissues which contained varying concentrations of target cells for amv transformation were analyzed to determine whether the expression of these proto-oncogenes resulted from, or was altered by, v-myb-induced leukemo ... | 1991 | 1886713 |
| development of an acid-soluble assay for measuring retrovirus integrase 3'-oh terminal nuclease activity. | a quantitative and efficient assay was developed to measure the 3'-oh terminal dna endonuclease activity of the avian myeloblastosis virus (amv) integrase protein. a retroviral-like linearized plasmid containing long terminal repeat (ltr) sequences at its recessed 3'-oh termini was filled in and labeled with the escherichia coli klenow dna polymerase fragment. the 32p-labeled nucleotide was located at the penultimate position. the labeled linearized plasmid or restriction fragments derived from ... | 1991 | 1888032 |
| v-myb transformation of xeroderma pigmentosum human fibroblasts: overexpression of the c-ha-ras oncogene in the transformed cells. | human xeroderma pigmentosum "normal" fibroblasts as16 (xp4 vi) were transformed after transfection with a recombinant v-myb clone. in this clone (pkxa 3457) derived from avian myeloblastosis virus (amv), the expression of the oncogene sequences is driven by the amv u-5 ltr promoter. the transformed cells (askxa), which have integrated a rearranged v-myb oncogene, grow in agar, are not tumorigenic in nude mice, and express a 45-kda v-myb protein. the hmw dna of these cells transform chicken embry ... | 1991 | 1893942 |
| some observations on the binding properties of alfalfa mosaic virus to polystyrene and its significance to indirect elisa. | the adsorption and retention properties of native (unfixed) and glutaraldehyde-fixed alfalfa mosaic virus (amv) antigens to the polystyrene of elisa plates were studied using [35s]-labelled virus preparations. it was shown that adsorption was a temperature-dependent, relatively slow process which varied between different amv isolates. the amount of virus antigen adsorbed was dependent on the type and ph of the suspending buffer. although native virus antigen adsorbed very efficiently at high ph ... | 1991 | 1902080 |
| preparation and characterization of immunoliposomes for targeting of antiviral agents. | antibodies specific to avian myeloblastosis virus envelope glycoprotein gp80 were raised. immunoliposomes were prepared using anti-avian myeloblastosis virus envelope glycoprotein gp80 antibody. the antibody was palmitoylated to facilitate its incorporation into lipid bilayers of liposomes. the fluorescence emission spectra of palmitoylated igg have exhibited a shift in emission maximum from 330 to 370 nm when it was incorporated into the liposomes. at least 50% of the incorporated antibody mole ... | 1991 | 1931020 |
| determinants of sequence-specific dna-binding by p48v-myb. | the v-myb oncogene of the avian myeloblastosis virus encodes a nuclear protein, p48v-myb, which binds to dna in a sequence-specific manner. we have used wild type and mutant forms of this protein expressed in e. coli to study the protein and dna determinants for sequence-specific dna-binding. we have shown that only the highly conserved domain at the amino terminus of p48v-myb is required for sequence-specific dna-binding. however, neither of the tandem 50 amino acid repeats present in this doma ... | 1991 | 2000220 |
| subsite specificity of the proteinase from myeloblastosis associated virus. | the subsite requirements of the aspartic proteinase from the myeloblastosis-associated virus (mav) for the cleavage of peptide substrates were studied with a series of synthetic peptides of general structure ala-thr-p4-p3-p2-p1*nph-val-arg-lys-ala. the residues in positions p4, p3, p2 and p1 were varied and the kinetic parameters for the cleavage of substrates in 2.0 m nacl were spectrophotometrically determined at ph 6.0 and 37 degrees c. the acceptance of amino acid residues in particular subs ... | 1991 | 2026269 |
| protein truncation is required for the activation of the c-myb proto-oncogene. | the protein product of the v-myb oncogene of avian myeloblastosis virus, v-myb, differs from its normal cellular counterpart, c-myb, by (i) expression under the control of a strong viral long terminal repeat, (ii) truncation of both its amino and carboxyl termini, (iii) replacement of these termini by virally encoded residues, and (iv) substitution of 11 amino acid residues. we had previously shown that neither the virally encoded termini nor the amino acid substitutions are required for transfo ... | 1991 | 2072904 |
| indirect double antibody sandwich elisa for detecting alfalfa mosaic virus in aphids after short probes on infected plants. | an indirect double antibody sandwich enzyme-linked immunosorbent assay (idas-elisa) system using antibodies elicited in rabbits and chickens is described for the detection of alfalfa mosaic virus (amv). the method is capable of detecting 40 pg of homologous purified amv and was shown to be suitable for detecting the virus in aphids. amv in the order of 150 pg was detected in single aphids. it was shown that a significant proportion of insects could acquire this or higher amounts of virus during ... | 1990 | 2086598 |
| the establishment of rat hybridoma cell lines secreting mcab against strains of potato virus y and analysis of its stability. | the rat splenocytes immunized with potato virus y (pvyn) and ratmyeloma (ir983) were fused by peg (m. w.1450). three kinds of stable hybridoma cell lines secreting specific monoclonal antibodies (mcabs) were derived. one kind of the cell lines producing mcabs reacts to pvyn specifically. another reacts to pvyo specifically. the third one reacts to both of the two strains. tested by the methods of sandwich-elisa and indirect-elisa, all kinds of mcabs did not react to seven plant viruses: tobacco ... | 1990 | 2104212 |
| novel fluorogenic substrates for assaying retroviral proteases by resonance energy transfer. | the 11-kd protease (pr) encoded by the human immunodeficiency virus 1 (hiv-1) is essential for the correct processing of viral polyproteins and the maturation of infectious virus, and is therefore a target for the design of selective acquired immunodeficiency syndrome (aids) therapeutics. to facilitate the identification of novel inhibitors of hiv-1 pr, as well as to permit detailed studies on the enzymology and inhibition of this enzyme, a continuous assay for its activity was developed that wa ... | 1990 | 2106161 |
| characterization of the v-myb dna binding domain. | the transforming protein encoded by the v-myb oncogene is a sequence-specific dna-binding protein that is thought to be involved in the regulation of gene expression. the n-terminal region of the v-myb protein is composed of two highly conserved tandem repeat sequences of unknown function. it has been speculated that the n-terminal v-myb repeats might be crucial for dna-binding, since n-terminal deletions destroy the dna-binding activity of the v-myb protein. here, we have studied the v-myb dna- ... | 1990 | 2110653 |
| differentiation and antigenic characterization of closely related alfalfa mosaic virus strains with monoclonal antibodies. | a panel of 15 mouse monoclonal antibodies (mabs) was raised against five strains of alfalfa mosaic virus (amv) which were closely related antigenically but biologically distinct. a wide diversity of mab specificity was revealed by screening them in three formats of indirect elisa, using native and glutaraldehyde-fixed amv particles as well as isolated coat protein preparations. of these mabs, seven reacted specifically with only one amv strain in at least one elisa format and at least one mab wa ... | 1990 | 2125636 |
| a temperature-sensitive phenotype of avian myeloblastosis virus: determinants that influence the production of viral mrnas. | the oncogene v-myb of avian myeloblastosis virus is expressed from an mrna that arises by splicing of the viral genome. in previous work, we described a mutant strain of avian myeloblastosis virus (tsamv) that elicits temperature-sensitive transformation and suggested that the mutation affects production of the mrna for v-myb. we now report that the principal determinant of the biochemical phenotype of tsamv is a point mutation located in a crucial region of the splice acceptor site for v-myb mr ... | 1990 | 2153241 |
| rna-binding properties of the matrix protein (p19gag) of avian sarcoma and leukemia viruses. | we have reinvestigated the ability of the matrix protein (ma) (p19gag) of avian sarcoma and leukemia viruses to interact with rna. previous reports claimed on the one hand that ma can bind tightly and with a high degree of specificity to avian sarcoma and leukemia virus rna in vitro and on the other that it cannot bind to rna at all. we found that ma purified by any of several methods does bind to rna, as measured by its ability to cause retention of radioactive rna on nitrocellulose membranes i ... | 1990 | 2153248 |
| heterogeneities in vertebrate trnas(trp) avian retroviruses package only as a primer the trna(trp) lacking modified m2g in position 7. | bovine, rabbit and chicken trna(trp) species and trna(trp) packaged in avian myeloblastosis virus were separated and purified using two-dimensional gel electrophoresis and their primary structures were determined. two major trna(trp) species (1 and 2) were identified in beef and rabbit, two minor ones (3 and 4) in beef and only one minor in rabbit. their structures differ by 4 nucleotide substitutions located in the d, s and t loops (positions 16, 47, 57 and 59). species 3 and 4 differ from one ... | 1990 | 2156227 |
| effects of 5' and 3' truncations of the myb gene on the transforming ability of avian myeloblastosis virus (amv). | proviruses based on the avian myeloblastosis virus (amv) have been constructed which code for variations of the c-myb and/or v-myb gene product. these proviruses have been used in a soft colony agar assay to assess the contributions of the 5' and 3' deletions of the v-myb oncogene in the cellular transforming activity of the virus. the results indicate that 3' truncations are an integral part of the gene's mechanism of activation and that the truncations on the 5' end of the gene are important e ... | 1990 | 2158185 |
| transformation by v-myb correlates with trans-activation of gene expression. | the v-myb oncogene of avian myeloblastosis virus causes acute myelomonocytic leukemia in chickens and transforms avian myeloid cells in vitro. its protein product p48v-myb is a nuclear, sequence-specific, dna-binding protein which activates gene expression in transient dna transfection studies. to investigate the relationship between transformation and trans-activation by v-myb, we constructed 15 in-frame linker insertion mutants. the 12 mutants which transformed myeloid cells also trans-activat ... | 1990 | 2160580 |
| binding properties of avian retroviral proteins. i. preparation and basic characterization of aslv nc(p12) and ma(p19). | using sp-sephadex column chromatography we isolated from an avian retrovirus, amv(mav), nucleic acid-binding proteins aslv nc(p12) and ma(p19). as shown by several criteria, namely sds-page, pr(p15) protease activity, and nucleic acid binding assay with the use of both ss and ds dnas, our nc(p12) and ma(p19) isolates are virtually pure proteins mutually not cross-contaminated. rabbit anti-nc(p12) and anti-ma(p19) sera which we prepared did not cross-react mutually. we conclude that both nc(p12) ... | 1990 | 2160893 |
| binding properties of avian retroviral proteins. ii. binding of protein aslv nc(p12) to viral rna and proviral dna. | binding of the major avian retroviral nucleocapsid protein aslv nc(p12) to the mav-1 (myeloblastosis-associated virus) proviral dsdna and viral ssrna was analysed using electron microscopy. specificity of the binding was estimated by special computer programs. the nc(p12) protein bound to mav-1 proviral dsdna (clone pat153--mav-1), but specificity of this binding was not found by computer evaluation. nc(p12) also bound to nondenatured 70s viral rna at a rate of 25 +/- 3 molecules per rna molecul ... | 1990 | 2160894 |
| binding properties of avian retroviral proteins. iii. binding of protein aslv ma(p19) to viral rna and proviral dna. | the binding of the avian retroviral matrix protein aslv ma(p19) to homologous viral ssrna and proviral dsdna was analysed using electron microscopic methods combined with a special computer evaluation. no binding affinity of ma(p19) to homologous nondenatured or denatured viral rna was found. in contrast, aslv ma(p19) was shown to have one specific binding site on mav-1 proviral dsdna at position 6795 +/- 345 bp from the 5' end of the molecule. a second specific binding site was found in a cellu ... | 1990 | 2160895 |
| distinct and different effects of the oncogenes v-myc and v-src on avian sympathetic neurons: retroviral transfer of v-myc stimulates neuronal proliferation whereas v-src transfer enhances neuronal differentiation. | immature avian sympathetic neurons are able to proliferate in culture for a limited number of divisions albeit expressing several neuron-specific properties. the effect of avian retroviral transfer of oncogenes on proliferation and differentiation of sympathetic neurons was investigated. primary cultures of 6-d-old quail sympathetic ganglia, consisting of 90% neuronal cells, were infected by myelocytomatosis virus (mc29), which contains the oncogene v-myc, and by the v-src-containing rous sarcom ... | 1990 | 2161856 |