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rna-dependent dna polymerase (reverse transcriptase) from avian myeloblastosis virus: a zinc metalloenzyme.rna tumor viruses contain a characteristic rna-dependent dna polymerase (reverse transcriptase) which has been thought to be related to the induction of leukemia by this virus. a disturbance in a zinc-dependent enzyme system was first postulated to account for the demonstrated differences in zinc metabolism of normal and leukemic leukocytes [vallee et al. in (1949) acta unio. int. contra cancrum 6, 869 and (1950) acta unio. int. contra cancrum 6, 1102]. in order to investigate the relationship b ...19744134617
effect of avian myeloblastosis virus in the japanese quail.moscovici, carlo (university of colorado medical center, denver), and e. h. macintyre. effect of avian myeloblastosis virus in the japanese quail. j. bacteriol. 92:1141-1149. 1966.-avian myeloblastosis virus (amv) induced a spectrum of neoplasms in japanese quail (coturnix coturnix japonica) which was similar to that observed in the chicken, with one exception: the total absence of acute myeloblastic leukemia in quail. studies in vivo as well as in vitro suggested that the cause for this differe ...19664288797
[synthesis of uridilic nucleotides and tmp in bone marrow of chickens infected with avian myeloblastosis virus]. 19684298767
effects of genetic cellular resistance on cell transformation and virus replication in chicken hematopoietic cell cultures infected with avian myeloblastosis virus (bai-a). 19684300361
studies on the rna from avian myeloblastosis virus. 19694302800
the oncogenic effects of nontransforming viruses from avian myeloblastosis virus. 19694308011
dna complementary to viral rna in leukemic cells induced by avian myeloblastosis virus.nucleic acid hybridization studies were made between 71s-amv-rna and dna from leukemic myeloblasts and from normal chicken cells. there was homology between the viral rna and chicken cell dna and to a greater extent between viral rna and leukemic cell dna. leukemic cell dna hybridized approximately twice as much viral rna as did normal chicken dna. thermal melting studies showed that the viral rna bound to normal and leukemic cell dna consists of long polynucleotides (t(m) = 87 degrees and 92 de ...19704317913
mitochondrial dna from cells transformed by avian myeloblastosis virus. 19714324717
early stimulation of dna synthesis in chicken fibroblasts infected by avian myeloblastosis virus. 19724333571
widespread presence, in chickens, of dna complementary to the rna genome of avian leukosis viruses.dna-rna hybridization experiments have demonstrated the widespread presence in chickens of dna complementary to the rna of avian myeloblastosis virus. all apparently normal chicken embryos, or adult chickens that were tested, contained viral dna in amounts ranging from 1.7 to 4.6 viral genome equivalents per cell. embryos that were negative or positive for the group-specific antigen of avian leukosis viruses contained the same amount of viral dna. embryos from a strain of chickens free of leukos ...19724335067
[avian myeloblastosis virus. model for study of leukemia due to virus]. 19714335902
endogenous rna-directed dna polymerase activity in uninfected chicken embryos.early chicken embryos that are either positive or negative for group-specific antigens of avian leukosis viruses contained endogenous rna-directed dna polymerase activity. this endogenous dna polymerase activity was not increased after mixture of soluble dna polymerases isolated from chicken embryos with disrupted chicken embryo cells. the endogenous activity was resistant to treatment with deoxyribonuclease, and the initial rate of dna synthesis was partially resistant to actinomycin d. in cont ...19724338597
[detection of avian myeloblastosis virus in chicken fibroblast cultures treated with dna from virus-producing leukemic cells]. 19724339978
structural studies on avian myeloblastosis virus: rapid purification and quantitation. 19724343190
distribution of deoxyribonucleic acid complementary to the ribonucleic acid of avian myeloblastosis virus in tissues of normal and tumor-bearing chickens.(3)h-labeled 70s ribonucleic acid (rna) from purified avian myeloblastosis virus (amv) was used as a probe in deoxyribonucleic acid (dna)-rna hybridization experiments to detect the presence of dna complementary to the amv genome in various tissues from noninfected normal chickens and from chickens infected with amv. there was a remarkable constancy in the average cellular concentration of virus-specific dna found in every tissue from the same uninfected chicken, and even in different chickens f ...19724344249
terminal nucleotides of avian myeloblastosis virus rna and of ribosomal rna from chicken leukemic myeloblasts. 19724347181
aminoacyl-trna synthetase activity in virions of avian myeloblastosis virus. 19734350587
quantitative determination and location of newly synthesized virus-specific ribonucleic acid in chicken cells infected with rous sarcoma virus.a sensitive and quantitative nucleic acid hybridization assay for the detection of radioactively labeled avian tumor virus-specific rna in infected chicken cells has been developed. in our experiments we made use of the fact that dna synthesized by virions of avian myeloblastosis virus in the presence of actinomycin d (amv dna) is complementary to at least 35% of the sequences of 70s rna from the schmidt-ruppin strain (srv) of rous sarcoma virus. annealing of radioactive rna (either srv rna or r ...19734350719
spontaneous regression of leukemia in chickens infected with avian myeloblastosis virus. 19734352529
identification of a large polypeptide precursor of avian oncornavirus proteins.antibody to partially disrupted avian myeloblastosis virus was used to selectively precipitate newly synthesized intracellular viral polypeptides from extracts of infected chicken cells. when analyzed by sodium dodecyl sulfate-gel electrophoresis, immune precipitates from extracts of cells pulse-labeled for 10 min with [(35)s]methionine contain none of the major virion polypeptides. instead they show prominent viral specific polypeptides of molecular weight 76,000 and 12,000, as well as minor qu ...19734352653
[resistance of german chicken lines against avian myeloblastosis virus (amv)]. 19734354748
chromatographic analyses of isoaccepting trnas from avian myeloblastosis virus.avian myeloblastosis virus (amv) 4s rna was tested for amino acid acceptor activity for 18 of the 20 amino acids. a nonrandom distribution of viral trnas was found compared with trna from normal liver or from amv-infected leukemic myeloblasts, confirming previous reports. methionine and proline trnas were considerably enriched, whereas glutamic acid, glutamine, serine, tyrosine, and valine trnas were markedly depleted in amv relative to homologous cellular trnas. the seven amv trnas with the gre ...19734355849
separation of dna sequences complementary to the rna of avian myeloblastosis virus from chicken dna by alkaline cesium chloride density sedimentation.density gradient sedimentation in alkaline cesium chloride of dna from normal chicken embryos or leukemic myeloblasts fragmented to a size of 13s revealed that the dna sequences complementary to 70s avian myeloblastosis virus rna sedimented in the high guanine plus cytosine region ahead of the main peak of cellular dna. when the dna was fragmented into pieces of 6.6s there was a broader distribution of the dna sequences complementary to the viral rna. this technique could be employed as a step t ...19734355853
integrated state of oncornavirus dna in normal chicken cells and in cells transformed by avian myeloblastosis virus.the covalent linkage of oncornavirus-specific dna to chicken dna was investigated in normal chicken embryo fibroblasts (cef) and in virus-producing leukemic cells transformed by avian myeloblastosis virus (amv). the virus-specific sequences present in cellular dna fractionated by different methods were detected by dna-rna hybridization by using 70s amv rna as a probe. in cef and in leukemic cells, the viral dna appeared to be present only in the nucleus. after cesium chloride-ethidium bromide de ...19734359950
presence in leukemic cells of avian myeloblastosis virus-specific dna sequences absent in normal chicken cells.(3)h-labeled 35s rna from purified avian myeloblastosis virus (amv) was exhaustively hybridized with an excess of normal chicken dna to remove all viral rna sequences which are complementary to dna from uninfected cells. the [(3)h]rna which failed to hybridize was isolated by hydroxylapatite column chromatography which separates dna-rna hybrids from single-stranded [(3)h]rna. the residual rna hybridized to leukemic chicken dna but did not rehybridize with normal chicken dna. this demonstrates co ...19744365719
virus release by cell colonies derived from chickens and cultures infected with avian myeloblastosis virus. 19744366504
reliability of the rna-dna filter hybridization for the detection of oncornavirus-specific dna sequences.denatured dna from leukemic myeloblasts or uninfected chicken embryos, immobilized on nitrocellulose filters, was hybridized to a vast excess of [(3)h]70s rna from purified avian myeloblastosis virus. the viral rna was eluted from the rna-dna hybrids, purified, and then rehybridized in solution to an excess of either leukemic or normal chicken embryonic dna. this study revealed that all the slow and the fast hybridizing viral rna sequences detectable by liquid hybridization in dna excess had hyb ...19744367899
transfection of chicken embryo cells with dna extracted from avian virus-producing neoplastic cells.dna isolated from avian virus-producing leukemic myeloblasts induced the production of viruses, but not morphological transformation, in cultivated chicken fibroblasts. the recovered virus had the same biological characteristics as the original avian myeloblastosis virus (amv) and produced myeloblastosis and nephroblastomas when injected into chickens. neutralization experiments with chicken anti-amv-bai strain a sera showed an antigenic community between the dna-transfected virus and the origin ...19744369392
differences between the integration of avian myeloblastosis virus dna in leukemic cells and of endogenous viral dna in normal chicken cells.the nature of integrated viral dna in normal and leukemic chicken cells has been studied by sequential nucleic acid hybridization procedures that localize the viral specific dna in cellular dna regions differing in reiteration frequency. first, dna.dna reassociation was employed to fractionate cellular dna sequences according to their reiteration frequencies. next, the dna in each fraction was denatured, immobilized on nitrocellulose filters, and then hybridized with viral [(3)h]rna. in normal c ...19744369920
protein synthesizing activities of ribosome-like structure isolated from avian myeloblastosis virus in chicken cell-free protein synthesis. 19744372573
isolation of avian nephroblastoma virus from avian myeloblastosis virus by the infectious dna technique. 19744375132
in vitro translation of fractionated rna isolated from chicken leukaemic plasma virus (amv). a 76k pol-related polypeptide.the 60s rna was isolated from amv-chicken leukaemic plasma virus. it was poly(a) selected, sized on sucrose gradients, and each fraction of rna translated in vitro in the rabbit reticulocyte lysate. it was shown by immunoprecipitation and peptide mapping that p76gag was translated from genome-length rna, a 76k pol-related polypeptide from 24-26s rna and a 34k protein, not related to any virion proteins, from 14s rna. the possible relationship of these in vitro translated proteins to known genome ...19846083884
avian erythroblastosis virus e26: nucleotide sequence of the tripartite onc gene and of the ltr, and analysis of the cellular prototype of the viral ets sequence.an intact 5.7-kb provirus of the avian erythroblastosis virus e26 has been molecularly cloned for comparisons with avian myeloblastosis virus (amv) and other avian tumor viruses. e26 and amv transform hemopoietic cells exclusively. both cause myeloblastosis, but e26 also causes erythroblastosis. sequence analysis of the proviral dna showed that: the tripartite transforming gene of e26 forms a contiguous reading frame of 1046 codons, including 272 gag, 283 mybe, and 491 ets codons. no subgenomic ...19846097027
induced differentiation of avian myeloblastosis virus-transformed myeloblasts: phenotypic alteration without altered expression of the viral oncogene.cells of a clone of avian myeloblastosis virus-transformed myeloblasts were induced to differentiate to adherent myelomonocytic cells by treatment with lipopolysaccharide. these adherent cells were subcultured and maintained as a line for more than 6 months with lipopolysaccharide present. cells of this line were induced to differentiate to nondividing macrophage-like cells by the addition of the tumor promoter 12-o-tetradecanoylphorbol-13-acetate. in this way, the following homogeneous cell pop ...19846098812
studies on the structure of avian myeloblastosis virus (amv) rna. ii. integrity of the rna in dependence on rna isolation and virus propagation.while sedimentation analysis revealed no basic changes in the sedimentation characteristics of 60-70 s avian myeloblastosis virus (amv) rna isolated under different conditions from two sources, electron microscopy exhibited differences in the length distributions of this rna. based on the length distribution profiles, phenol extraction showed a higher degradation effect in comparison with direct gradient centrifugation of viral lysates. proteinase k appeared to be a more suitable nuclease inhibi ...19826124106
radioimmunological comparison of the dna polymerases of avian retroviruses.125i-labeled dna polymerases of avian myeloblastosis virus and spleen necrosis virus were used in a radioimmunological characterization of avian retrovirus dna polymerases. it was shown that avian leukosis virus and reticuloendotheliosis virus dna polymerases do not cross-react in radioimmunoassays. within the avian leukosis virus species, species-specific and type-specific antigenic determinants of the dna polymerase were defined. the previous finding of genus-specific antigenic determinants in ...19806154153
inhibition of virion-associated reverse transcription by nucleoside triphosphatase in avian myeloblastosis virus.rna-dependent dna polymerase activity of avian myeloblastosis virions as measured by the incorporation of [3h]ttp into trichloroacetic acid-precipitable material was very low. this apparent low polymerase activity was observed with virions isolated either from leukemic chicken plasma or from the supernatant of cultured leukemic myeloblasts. the inhibition of reverse transcriptase activity was caused by nucleoside triphosphatase present in avian myeloblastosis virions and could be reversed by adp ...19806154806
genetic structure of avian myeloblastosis virus, released from transformed myeloblasts as a defective virus particle.chicken myeloblasts transformed by avian myeloblastosis virus (amv) in the absence of nondefective helper virus (termed nonproducer cells) were found to release a defective virus particle (dvp) that contains avian tumor viral gag proteins but lacks envelope glycoprotein and a dna polymerase. nonproducer cells contain a pr76 gag precursor protein and also a protein that is indistinguishable from the pr180 gag-pol protein of nondefective viruses. the rna of the dvp is 7.5 kilobases (kb) long and i ...19806159639
characterization of an inhibitor of granulocyte/monocyte colony formation in leukemic chicken plasma.the plasma of chicks with myeloblastic leukemia (induced by avian myeloblastosis virus, amv) contained an inhibitor which blocked colony formation in vitro by marrow cells. it eluted in the second protein peak obtained by sephadex g-200 gel filtration and was found in the diafiltrate following defiltration through a um 10 membrane under acidic conditions. it was not extractable with chloroform, was heat-stable (65 degrees c, 30 min), pronase-sensitive and had a molecular weight less than or equa ...19816165604
reverse transcriptase associated with avian sarcoma-leukosis viruses. i. comparison of intra-virion content of multiple enzyme forms.the rna-dependent dna polymerase (the reverse transcriptase) was solubilized from three related strains of avian sarcoma virus (asv b77, asv tsla334, and asv qv2) as well as avian myeloblastosis virus (amv) and a chicken endogenous virus (rav-o), by a combination of non-ionic detergent treatment and cscl step-gradient centrifugation, and was subsequently separated into individual enzyme forms by poly(c)-agarose column chromatography. the newly developed two-step method allowed us to purify the t ...19826175623
lymphoid leukosis: detection of group specific viral antigen in chicken spleens by immunofluorescence and complement fixation.monospecific antiserum obtained from rabbits hyperimmunized against homogeneous p27 group specific protein purified from avian myeloblastosis virus was commercially procured and was then conjugated with fluorescein isothiocyanate. the conjugate was applied to spleens from naturally or experimentally infected chickens that had no evidence of lymphoid tumors. fluorescence was usually localized in connective tissue of sheathed capillaries giving it a ring-like appearance. sites of fluorescence corr ...19826184143
mechanism of action of the endonuclease associated with the alpha beta and beta beta forms of avian rna tumor virus reverse transcriptase.preparations of the alphabeta and the betabeta forms of reverse transcriptase from the prague c strain of rous sarcoma virus grown in chicken embryo fibroblasts, the alphabeta and the betabeta forms of the enzyme from the b77 strain of rous sarcoma virus grown in duck embryo fibroblasts, and the alphabeta form of reverse transcriptase from avian myeloblastosis virus have been analyzed. all these enzyme preparations contain a mn(2+) -activated endonuclease activity. the betabeta form of enzyme, i ...19836187936
the human dna locus related to the oncogene myb of avian myeloblastosis virus (amv): molecular cloning and structural characterization.chicken and human cell dna contains sequences homologous to the avian myeloblastosis virus oncogene, v-myb. these cellular sequences, c-myb (human) and c-myb (chicken), were isolated from libraries of human or chicken cell dna fragments, generated by partial digestion with the restriction enzymes alui and haeiii, and compared. the chicken c-myb locus isolated from two distinct overlapping recombinant phages, contained five contiguous ecori fragments of 5.4, 1.1, 2.1, 2.2 and 9 kbp, accounting fo ...19836194989
[isolation of reverse transcriptase from the avian myeloblastosis virus in preparative quantities].inverse transcriptase of bird myeloblastosis virus is a unique instrument for artificial synthesis of structural genes of viruses, plants, animals. methods for the virus production in preparative amounts are developed due to selection of the corresponding line of chickens, conditions of their maintenance, diet infection methods and myeloblastosis diagnostics. main demands to the inverse transcriptase preparations (their high activity, absence of nuclease impurities, high concentration of the enz ...19846209836
detection of avian oncovirus group-specific antigens by the enzyme-linked immunosorbent assay.a three-step sandwich enzyme-linked immunosorbent assay was developed for the detection of avian oncovirus group-specific (gs) antigens. the assay procedure was to coat the wells of microtitre plates with hamster anti-gs igg, react with crude or purified antigen and finally with hamster anti-gs igg linked to horseradish peroxidase. the sensitivity was 8 picograms (pg) of input avian myeloblastosis virus (amv) protein, with negligible background. as the elisa takes less than 2 h to perform, large ...19806245172
characterization of avian myeloblastosis-associated virus dna intermediates.the major species of unintegrated linear viral dna identified in chicken embryonic fibroblasts infected with either the avian myeloblastosis-associated viruses (mav-1, mav-2) or the standard avian myeloblastosis virus complex (amv-s) has a mass of 5.3 x 10(6) daltons. an additional minor dna component observed only in amv-s-infected cells has a mass of 4.9 x 10(6) daltons. the unintegrated linear viral dnas and integrated proviruses of mav-1 and mav-2 have been analyzed by digestion with the res ...19806246269
pathology of chickens infected with avian nephoblastoma virus mav-2(n).a neophroblastoma-inducing myeloblastosis-associated virus, mav-2(n), derived from avian myeloblastosis virus was characterized with respect to biochemical composition and avian pathogenesis. purified fibroblast-grown virus contained the same size 35s ribonucleic acid and the same relative amounts of viral polypeptides as another myeloblastosis-associated virus inducing predominantly osteopetrosis mav-2(o). plaque-purified mav-2(n) induced a 76 to 93% incidence of nephroblastoma and a 3 to 50% i ...19806247276
identification of a proviral genome associated with avian myeloblastic leukemia.we have identified and isolated a presumptive leukemogenic provirus from myeloblasts of a chicken in which leukemia had been induced by avian myeloblastosis virus (amv). leukemic myeloblasts isolated from peripheral blood or from converted yolk sac cultures of various strains of chickens, regardless of the endogenous proviral content or amv pseudotype used for infection, contain an ecori 2.2-megadalton (mdai) and a hindiii 2.6-mdal proviral fragment. a proviral genome flanked by chicken dna sequ ...19806248880
avian myeloblastosis virus proteins in leukemic chicken myeloblasts.we have analyzed the avian myeloblastosis virus proteins in two types of leukemic myeloblasts: established myeloblastic cell lines (du 1765 and du 11157) and leukemic myeloblasts obtained from the peripheral blood of a leukemic c/e spafas chicken (no. 21957). using monospecific antisera for immunoprecipitation and polyacrylamide gel electrophoresis, we have detected gag gene-related proteins in the myeloblasts. the du 1765 and du 11157 cells contained a p100 protein which possessed antigenic det ...19806252337
dna of avian myeloblastosis-associated virus type 2 integrates at multiple sites in the chicken genome.the cellular sites of integration of the avian myeloblastosis-associated virus type 2 (mav-2) dna have been examined by southern blot analysis of cellular dna from infected cloned and uncloned chicken embryonic fibroblasts. provirus-cell juncture fragments were not detected in restriction enzyme digests of dna from mav-2-infected uncloned cells. however, each mav-2-infected cell clone examined produced a unique set of junctive bands. thse findings indicate that multiple sites of integration exis ...19806252351
identification of the avian myeloblastosis virus genome. i. identification of restriction endonuclease fragments associated with acute myeloblastic leukemia.the proviral dna of chicken peripheral blood leukemic myeloblasts was analyzed by restriction endonuclease digestion and southern blotting. two restriction endonuclease-generated fragments, an ecori 2.2-megadalton (md) and a hindiii 2.6-md fragment, were present upon enzyme cleavage of all leukemic myeloblast dna preparations in addition to endogenous or helper-specific fragments. neither of these fragments was derived from viral dna of the two known myeloblastosis-associated viruses (mav-1 and ...19806253658
identification of the avian myeloblastosis virus genome. ii. restriction endonuclease analysis of dna from lambda proviral recombinants and leukemic myeoblast clones.two lambda proviral dna recombinants were characterized with a number of restriction endonucleases. one recombinant contained a complete presumptive avian myeloblastosis virus (amv) provirus flanked by cellular sequences on either side, and the second recombinant contained 85% of a myeloblastosis-associated virus type 1 (mav-1)-like provirus with cellular sequences adjacent to the 5' end of the provirus. comparing the restriction maps for the proviral dnas contained in each lambda hybrid showed ...19806253659
retroviral antigens on gs- chf- leukocytes.it has recently been suggested that the endogenous retroviruses present in many different species might be involved during stimulation of the immune system of their hosts. we have now studied the expression of two avian retroviral antigens p27 and gp85 in chicken lymphoid cells by indirect immunofluorescence (iif) and by complement-dependent microcytotoxicity (cdm). we have now found that these viral antigens are expressed in peripheral blood leukocytes of adults and embryos and in splenic and b ...19806253834
cellular sequences are present in the presumptive avian myeloblastosis virus genome.ecori restriction endonuclease fragments from a lambda proviral dna hybrid containing the entire presumptive avian myeloblastosis virus (amv) provirus, and from a lambda proviral hybrid containing a partial myeloblastosis-associated virus type 1 (mav-1)-like provirus were compared by heteroduplex analysis. the cloned presumptive amv provirus was also analyzed by electron microscopy, using r-loop formation with purified 35s rna isolated from virions of the standard amv complex. the results indica ...19806254063
activation of cellular genes by avian rna tumor viruses.we demonstrated previously that chicken embryo fibroblasts accumulate approximately 100 copies of embryonic globin rna after transformation by rous sarcoma virus. here we demonstrate that the globin gene in chicken embryo fibroblasts is activated by infection with two other oncogenic retroviruses, avian erythroblastosis virus and strain mc-29 of avian myeloblastosis virus, which contain transforming genes unrelated in nucleotide sequence content to each other or to the rous sarcoma virus src gen ...19806254077
expression of endogenous avian myeloblastosis virus information in different chicken cells.uninfected chicken cells were found to contain endogenous avian myeloblastosis virus (amv)-specific information. different tissues from chicken embryos and chickens expressed different amounts of the amv-specific information. the endogenous amv-related rna was most abundant in bone marrow cells, which contained about 20 copies per cell. about 5 to 10 copies of amv endogenous rna per cell were found in embryonic yolk sac cells and bursa cells. the spleen, muscle, liver, and kidney cells of chicke ...19806255203
virus-mediated abrogation of chicken lymphocyte responsiveness to mitogenic stimulus.we have found that various sorts of virus particles, including avian leukosis and sarcoma viruses, sendai virus, friend leukemia virus and murine mammary tumor virus, are able, upon coincubation with chicken peripheral lymphocytes and either concanavalin a (con a) or phytohemagglutinin (pha), to inhibit the mitogenic responses that normally follow. such inhibition is not dependent on the use of infectious virus, and can be documented by using particles whose infectivity has been abolished by irr ...19806255923
studies in amv dna. i. physical properties and sequence composition of dna present in amv virions (amv dna).the basic physical properties of amv dna (labeled with 3h-thymidine) as well as sequence homology between 3h-amv dna and viral or host cell genomes were investigated. it was found that native amv dna is in part single-stranded (20% of the total dna). using cscl density gradient centrifugation amv dna was separated into two bands with buoyant densities of 1.702 g/cm3 (l-amv dna) and 1.722 g/cm3 (h-amv dna) in the peak fractions. corresponding melting temperatures were estimated to be 82.0 degrees ...19806257200
replicating, differentiated macrophages can serve as in vitro targets for transformation by avian myeloblastosis virus.pure cultures of chicken macrophages were characterized functionally and transformed by avian myeloblastosis virus. transformed cells exhibited an altered function. the efficiency of transformation was limited by the mitotic activity of the macrophages.19816260997
histone h5 in the immature blood cells of chickens with leukosis induced by avian leukosis virus strain e26.whole histone was isolated from the immature cells of the peripheral blood of white leghorn chickens, line 151, with leukosis experimentally induced by avian leukosis virus, strain e26 (alv-e26). histone h5 was demonstrated in all samples of these cells and was characterized by electrophoresis in polyacrylamide gel, extraction with perchloric acid, amino acid analysis, and immunodiffusion in agarose gel. histone h5 was not detected in the myeloblasts of chickens with myeloblastosis caused by the ...19816264195
oncogenicity of three strains of avian leukosis virus in white leghorn chicks of bk line. 19806265807
vertebrate dnas contain nucleotide sequences related to the transforming gene of avian myeloblastosis virus.avian myeloblastosis virus contains a continuous sequence of approximately 1,000 nucleotides which may represent a gene (amv) responsible for acute myeloblastic leukemia in chickens. this sequence appears to have been acquired from chicken dna and to be substituted for the envelope gene in the viral genome. we used hybridization probes enriched for the amv sequences and conditions that facilitate annealing of partially homologous nucleotide sequences to show that cellular sequences related to am ...19816275098
characterization of reticuloendotheliosis virus strain t dna and isolation of a novel variant of reticuloendotheliosis virus strain t by molecular cloning.reticuloendotheliosis virus strain t (rev-t) is a highly oncogenic avian retrovirus which causes a rapid neoplastic disease of the lymphoreticular system. upon infection, this virus gives rise to two species of unintegrated linear viral dna, which are 8.3 and 5.5 kilobase pairs long and represent the helper virus (rev-a) and the oncogenic component (rev-t), respectively. restriction endonuclease cleavage maps of these two dna components indicate that rev-t dna has a large portion of the genome d ...19816275117
helper viruses associated with avian acute leukemia viruses inhibit the cellular immune response. 19826278717
transcription of the chicken alpha 2 (type i) collagen gene by homologous cell-free extracts.we have used two methods to detect specific transcription of the chicken alpha 2 (type i) collagen gene in cell-free extracts derived from rous sarcoma virus-transformed chicken embryo fibroblasts. the first method is a modification of the s1 nuclease mapping procedure which utilizes a dna probe labeled with 32p at the 5' end of the hindiii linker originally used to clone the collagen promoter region into pbr322. the probe distinguishes newly made, specific rna from endogenous rna and nonspecifi ...19826282836
avian myeloblastosis virus transforming gene is related to unique chicken dna regions separated by at least one intervening sequence.identification of several additional restriction endonuclease sites within the cellular substitution (amv) inserted into the avian myeloblastosis virus proviral genome has permitted us to isolate different regions of the amv sequence. these subsets of the avian myeloblastosis virus transforming gene have been cloned in the plasmid pbr322 and used as hybridization probes to investigate the topology of homologous (proto-amv) normal chicken dna sequences. the results showed that the cellular proto- ...19826283118
genome of reticuloendotheliosis virus: characterization by use of cloned proviral dna.reticuloendotheliosis virus is an avian type c retrovirus that is capable of transforming fibroblasts and hematopoietic cells both in vivo and in vitro. this virus is highly related to the three other members of the reticuloendotheliosis virus group, including spleen necrosis virus, but it is apparently unrelated to the avian leukosis-sarcoma virus family. previous studies have shown that it consists of a replication-competent helper virus (designated rev-a) and a defective component (designated ...19826283142
acute leukemia viruses e26 and avian myeloblastosis virus have related transformation-specific rna sequences but different genetic structures, gene products, and oncogenic properties.replication-defective acute leukemia viruses e26 and myeloblastosis virus (amv) cause distinct leukemias although they belong to the same subgroup of oncogenic avian tumor viruses based on shared transformation-specific (onc) rna sequences. e26 causes predominantly erythroblastosis in chicken and in quail, whereas amv induces a myeloid leukemia. however, upon cultivation in vitro for >1 month, a majority of surviving hemopoietic cells of e26-infected animals bear myeloid markers similar to those ...19826285358
immune stimulation of sensitized chicken lymphocytes by avian retrovirus proteins.peripheral blood lymphocytes of chickens bearing tumours induced by avian sarcoma virus can be specifically stimulated to divide by the crude culture fluids of virus-infected cells. in this communication, we show that relevant antigenic activity apparently resides in each of the internal virus proteins p15 and p27. the ability of infectious culture fluids to be mitogenic for sensitized lymphocytes is greatly reduced following treatment with antibodies specific for either total avian myeloblastos ...19826286858
avian myeloblastosis provirus cloned in a lambda bacteriophage is leukemogenic.the avian myeloblastosis virus provirus inserted in a lambda bacteriophage, recombinant clone 11a1-1 (souza et al., proc. natl. acad. sci. u.s.a. 77:3004-3008, 1980), was transfected into chicken embryo fibroblasts which had been preinfected with either rous-associated virus type 61 or the transformation-defective avian sarcoma virus tdb77. within 4 to 5 h after transfection, the cells were injected into 16-day-old chicken embryos or 1-day-old chicks. acute myeloblastic leukemia developed after ...19826292502
organization of chicken dna sequences homologous to the transforming gene of avian myeloblastosis virus. i. restriction enzyme analysis of total dna from normal and leukemic cells.hybridization probes consisting of cloned dna recombinants which represent different regions of the leukemogenic sequence (amv) from avian myeloblastosis virus were used to carry out a more detailed restriction endonuclease analysis of the homologous sequences (proto-amv) present in normal and leukemic chicken dna. the results show that four large introns interrupt the normal cellular proto-amv sequences and that there is no major rearrangement of these sequences in leukemic myeloblasts.19826292519
transforming ability of avian defective leukemia viruses in early embryogenesis.the response to infection of chicken hemopoietic cells derived from the early stages of embryogenesis by avian myeloblastosis virus (amv) and avian erythroblastosis virus (aev) was investigated. it was found that erythroid progenitor cells were present in the blastoderm at a higher frequency than that of myeloid progenitor cells. these results correlate with the observation that target cells for aev were found to be more numerous than those for amv. therefore, blastoderm cells are of potential v ...19836297153
transformation of both erythroid and myeloid cells by e26, an avian leukemia virus that contains the myb gene.e26 and avian myeloblastosis virus are replication-defective avian retroviruses that contain the myb oncogene and cause leukemia in chickens with short periods of latency. animals infected with e26 develop erythroleukemia and also contain low numbers of transformed myeloid cells, while avian myeloblastosis virus induces a purely myeloid leukemia. in both cases the type of leukemia induced is independent of the subgroup of the helper virus used. e26-transformed erythroid and myeloid cells can eac ...19826297778
structure and transcription of the cellular homolog (c-myb) of the avian myeloblastosis virus transforming gene (v-myb).we isolated and characterized molecular clones containing the chicken cellular homolog (c-myb) of the avian myeloblastosis virus oncogene (v-myb). mapping of the c-myb clones using restriction endonucleases and hybridization to radiolabeled v-myb probes revealed that the sequences homologous to v-myb are contained within four separate regions, which have since been shown by nucleotide sequencing (klempnauer et al., cell 31:453-463, 1982) to carry seven exons. analysis of c-myb transcripts showed ...19836298458
isolation and characterization of a temperature-sensitive mutant of avian myeloblastosis virus.a temperature-sensitive (ts) mutant, ga 907/7, was isolated after mutagen treatment of avian myeloblastosis virus. when bone marrow cells or secondary yolk sac macrophages were infected with ga 907/7, the expression of transformation was greatly reduced at 41 degrees c. the results of temperature-shift experiments suggest that in ga 907/7 the putative v-myb gene product is functional only at 35.5 degrees c. moreover, when ts-induced transformed cells were shifted to 41 degrees c, a partial morph ...19836298790
detection of avian hematopoietic cell surface antigens with monoclonal antibodies to myeloid cells. their distribution on normal and leukemic cells of various lineages.the isolation and characterization of monoclonal antibodies reacting with cell surface antigenic determinants of normal and leukemic avian hematopoietic cells is described. the antibodies were produced by immunizing mice with normal macrophages, as well as with myeloid cells transformed with the avian acute leukemia viruses mc29, amv and e26. eleven antibodies were characterized for their reactivity with a variety of normal and leukemic cells of the myeloid, b- and t-lymphoid and of the erythroi ...19836299767
modulation of atpase activity of avian myeloblastosis virus with ca2+, atp & its reaction products. 19826299931
organization of chicken dna sequences homologous to the transforming gene of avian myeloblastosis virus. ii. isolation and characterization of lambda proto-amv dna recombinant clones from a library of leukemic chicken dna.several lambda proto-amv recombinants isolated from a lambda charon 4a library of leukemic chicken dna were analyzed by using various restriction endonucleases and hybridization with specific probes representing different regions of the transforming gene of avian myeloblastosis virus. the position of 30 sites for 11 different restriction endonucleases was established in the proto-amv region of chicken dna. identical restriction endonuclease maps were obtained for the normal and leukemic dnas in ...19836300463
avian myeloblastosis virus: a model for the generation of viral oncogenes from potentially oncogenic cellular genetic elements. 19836301896
a monoclonal antibody with specificity for leukemic cells transformed by defective avian leukemia viruses.mouse anti-chicken monoclonal antibodies were raised against an avian myeloblastosis virus (amv)-transformed myeloblastic leukemic cell line. one monoclonal antibody, s1-37 (igg2a), reacted with producer and nonproducer myeloblastic leukemia cell lines transformed by amv and by e-26 virus, but it did not react with chicken fibroblasts infected with rav-2, mav-2, mav-1, or rav-7. s1-37 also did not react with normal chicken hemopoietic cells, except for yolk sack macrophages and a small populatio ...19826302112
nucleotide sequence and organization of the transforming region and large terminal redundancies (ltr) of avian myeloblastosis virus (amv).avian myeloblastosis virus (amv) is a replication-defective acute leukemia virus, requiring a helper virus to provide the viral proteins essential for synthesis of new infectious virus. the genome of the amv has undergone a sequence substitution in which a portion of the region normally coding for the "env" protein has been replaced by chicken cellular sequences. these latter sequences are essential for the transforming activity of the virus. we have determined the complete nucleotide sequence o ...19826302118
identification of the leukemogenic protein of avian myeloblastosis virus and of its normal cellular homologue.the genome of the replication-defective avian myeloblastosis virus (amv) contains an inserted cellular sequence (amv) that is part of the oncogene responsible for acute myeloblastic leukemia in chickens infected with amv. three antisera raised against distinct synthetic peptides predicted from the long open reading frame of amv specifically precipitated the same 48-kilodalton protein (p48amv) from leukemic myeloblasts but not from normal hematopoietic tissue, fibroblasts, or from fibroblasts inf ...19836304685
the product of the retroviral transforming gene v-myb is a truncated version of the protein encoded by the cellular oncogene c-myb.avian myeloblastosis virus (amv) is an oncogenic retrovirus that rapidly causes myeloblastic leukemia in chickens and transforms myeloid cells in culture. amv carries an oncogene, v-myb, that is derived from a cellular gene, c-myb, found in the genomes of vertebrate species. we constructed a plasmid vector that allows expression of a portion of the coding region for v-myb in a procaryotic host. we then used the myb-encoded protein produced in bacteria to immunize rabbits. the antisera obtained p ...19836305504
tripartite structure of the avian erythroblastosis virus e26 transforming gene.only two avian oncogenic viruses specifically cause acute leukaemias yet do not transform chicken fibroblasts in culture: e26, which causes erythroblastosis and a low level of concomitant myeloblastosis in chickens, and avian myeloblastosis virus (amv), which causes myeloblastosis exclusively. both viruses are replication-defective and share a sequence termed myb (also known as amv) which is unrelated to essential virion genes and is therefore thought to be part of the transforming onc genes of ...19836316155
a putative second cell-derived oncogene of the avian leukaemia retrovirus e26.the acute avian leukaemia retroviruses amv and e26 both induce myeloblastosis in vivo and transform myeloblasts in vitro. both viruses contain the oncogene v-myb first described for amv. unlike amv, e26 has the additional capacity to induce erythroblastosis in vivo and to transform erythroblasts. previous analyses indicated that the genome of e26 also contained nucleotide sequences distinct from v-myb and unrelated to viral replicative genes. using a molecularly cloned e26 provirus, we have now ...19836316156
presence of actin in oncornaviruses.a 43k protein present in avian myeloblastosis virus has been identified as actin by 2d gel electrophoresis and peptide mapping proteolysis. electron microscopy of chicken embryo fibroblasts infected with different pseudotypes of oncornaviruses treated with anti-actin antibody showed positive staining at the level of the virions especially on buds. our results indicate that this actin is unlikely to have been artefactually absorbed at the virion surface during its preparation. it may therefore pl ...19846322753
subcellular localization of proteins encoded by oncogenes of avian myeloblastosis virus and avian leukemia virus e26 and by chicken c-myb gene.analysis of the subcellular location of the proteins encoded by the oncogenes of avian myeloblastosis virus and avian leukemia virus e26 ( p45v -myb and p135gag -myb-ets, respectively) and by the chicken c-myb gene ( p75c -myb) shows that all three proteins are located in the nucleus. in amv-infected (but not transformed) chicken fibroblasts p45v -myb also resides in the nucleus, indicating that a nuclear location of p45v -myb in these cells is not sufficient to achieve transformation. in amv-tr ...19846327074
myeloblasts transformed by the avian acute leukemia virus e26 are hormone-dependent for growth and for the expression of a putative myb-containing protein, p135 e26.avian leukemia virus e26 contains the myb oncogene and transforms erythroid and myeloid hematopoietic cells in vivo and in vitro. e26-transformed nonproducer myeloblasts but not avian erythroleukemia virus (aev)-transformed erythroblasts nor mc29-transformed macrophages were shown to be dependent for growth on factor(s) present in supernatants from concanavalin a-stimulated chicken spleen cells. the same factor enhanced the synthesis of p135 e26, the candidate transforming protein of e26, but di ...19826329725
chromosomal localization of the human proto-oncogene c-ets.e26 is an acute leukaemia avian retrovirus which induces myeloblastosis and erythroblastosis in vivo and transforms erythroblasts and myeloblasts in vitro. it contains the oncogene v-myb (ref. 4), first described for avian myeloblastosis virus (amv), as well as a second specific nucleotide sequence, v-ets located 3' to v-myb (refs 5,6). we have reported that v-ets has a cellular counterpart (c-ets) in chicken and human dna. now, using two independent methods--hybridization with human c-ets probe ...19846462246
[mechanism of virus-induced leukemogenesis in an animal model system].retroviruses can cause different types of leukemias in chickens. a small group of virus strains induce acute leukemias and transform hematopoietic cells in vitro. we have shown that cells transformed in vitro by erythroblastosis and myeloblastosis viruses resemble in vivo transformed cells in their phenotype of differentiation. the erythroblastosis virus aev carries two cell-derived oncogenes termed erba and erbb. the analysis of aev using deletion mutants showed that erbb is the main oncogene w ...19846471771
target cells for avian myeloblastosis virus in embryonic yolk sac and relationship of cell differentiation to cell transformation.the yolk sac of the 12-day chicken embryo retains the blast stage progenitors to cells of the myeloid lineages with a very low level of contamination by more mature myeloid cells which have begun to express the characteristic myeloid cell markers. both in vivo and in vitro experiments have supported the hypothesis that target cells for the bai-a strain of avian myeloblastosis virus are contained within the myeloid lineages. an assay system for avian myeloblastosis virus was developed which utili ...19846699939
purification and characterization of the rna-directed dna polymerase of a primate type-d retrovirus: mason-pfizer virus.the rna-directed dna polymerase of the primate type-d retrovirus mason-pfizer virus was purified using ion-exchange and affinity chromatography, and molecular sieving. the enzyme was shown to have a molecular weight of approx. 80 000 as determined by sedimentation analysis, molecular sieving and sodium dodecyl sulfate polyacrylamide gel electrophoresis. the purified rna-directed dna polymerase retained its ability to use a heteropolymeric rna as a template. the mason-pfizer virus rna-directed dn ...19806772221
a cloned calmodulin structural gene probe is complementary to dna sequences from diverse species.calmodulin mrna has been partially purified from a total nucleic acid extract of the electroplax of electrophorus electricus by oligo(dt)-cellulose chromatography and sucrose gradient centrifugation. a 9- to 10s fraction was determined to contain 39% calmodulin mrna by translation in a reticulocyte lysate followed by immunoprecipitation with antibodies to calmodulin. double-stranded cdna was synthesized from the rna fraction by using reverse transcriptase from avian myeloblastosis virus. the dou ...19816941292
differential expression of the amv gene in human hematopoietic cells.total cellular rnas from a variety of fresh and culture-derived human hematopoietic neoplastic cell types at various stages of differentiation and human sarcoma, carcinoma, melanoma, and glioblastoma cell lines were enriched for poly(a)- containing sequences, fractionated by gel electrophoresis, and blot hybridized to a cloned dna probe containing the transforming sequences (v-amv) of avian myeloblastosis virus (amv), a virus known to cause myeloid leukemias in chickens. expression of rna sequen ...19826954533
levels of colony-stimulating and inhibiting activities in chicks with myeloblastic leukemia are related to disease progression.chicks with myeloblastic leukemia induced by avian myeloblastosis virus (amv) exhibited increased levels of plasma granulocyte/monocyte (gm) colony-stimulating activity (csa). chromatography of plasma from amv-infected chicks revealed that this csa eluted in the first protein peak from a column of sephadex g-200. a second protein peak from the same column contained an inhibitor of gm colony-formation. the presence of the inhibitor and the increased csa was studied during the development of myelo ...19826978259
recombinant plasmids containing avian vitellogenin structural gene sequences derived from complementary dna.purified mrna coding for chicken vitellogenin, a precursor of egg yolk proteins, was transcribed to complementary dna (cdnavit) with avian myeloblastosis virus (amv) reverse transcriptase. double-stranded cdna was synthesized with escherichia coli dna polymerase i (fragment a) using the self priming ability of the cdna. following s1 nuclease digestion the double-stranded cdna was inserted into the hind iii site of plasmid pbr322 using the poly(da) . poly(dt) tailing method, and the hybrid molecu ...19806986172
changes in the expression of membrane antigens during the differentiation of chicken erythroblasts.chicken erythroblasts can be transformed by the avian retrovirus, avian erythroblastosis virus (aev). earlier studies have shown that the mechanism of transformation appears to involve a "block" in differentiation, in that when erythroblasts are transformed by a temperature-sensitive mutant of ts34 aev and incubated at the nonpermissive temperature, the cells start to differentiate and produce hemoglobin. we have decided to use this system to isolate pure populations of chicken erythroblasts and ...19827040433
collagen and noncollagen protein synthesis in chick limb bud cells infected with a virus that causes osteoblastoma.infection of cultured stage 24 (day 4.5) chick limb cells (spot cultures) with myeloblastosis-associated virus 2-(osteo) (mav-2(0)) produces cell density-dependent alterations of collagen and noncollagen protein synthesis over the course of 8 days in culture. collagen synthesis in infected, low density cultures (100 k cells/spot) was maximal on day 4 and increased 12 fold compared with maximal values on days 5-6 for uninfected counterparts. the patterns of collagen synthesis were similar in unin ...19817289876
[dna polymerase in the microsomal fraction of the myeloblasts of chickens infected with avian myeloblastosis virus].only one dna polymerase is present in the microsomal fraction of the cells producing amv. chromatographically purified enzyme shows the properties of revertase, that is it transcribes in dna the information encoded in natural rna. the enzyme possesses identical chromatographic characteristics and the same template specificity as the enzyme isolated from pure amv virus. thus the virus enzyme and the cellular dna polymerase from the microsomal fraction cannot be differentiated on the basis of cert ...19807293688
in vitro translation of fractionated virus-specific rna isolated from plasma of chicken infected by avian myeloblastosis virus. unprocessed and processed myeloblastosis-associated virus env-polypeptide precursors.the 60 s viral rna complex isolated from leukaemic plasma of chicken infected by avian myeloblastosis virus (amv) was denatured, the poly(a)-rna selected and centrifuged in a linear sucrose density gradient. rna from each fraction was translated in vitro and the products were analyzed by slab polyacrylamide gel electrophoresis (page). unprocessed primary translation product (p64env) of mav env gene from 21 s rna fraction was immunoprecipitated by anti-gp85 serum. if, however, this rna was transl ...19937516622
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