Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| [enzymology of reverse transcription]. | 1980 | 6158678 | |
| study of the interactions between avian myeloblastosis virus reverse transcriptase and primer trna. affinity labeling and inactivation of the enzyme by periodate-treated trnatrp. | reverse transcriptase from avian myeloblastosis virus can react with periodate-treated primer trnatrp (beef) to form a schiff's base between an epsilon-nh2 lysine group within the active center of the enzyme and the dialdehyde derivative of the 3' terminal ribose of trna. in the presence of cyanoborohydride the reversible imminium moiety of the schiff's base is reduced to a more stable adduct. non-primer trnas were not able to reduce the extent of primer fixation to the enzyme. complete inactiva ... | 1980 | 6160474 |
| native ribonucleoprotein is an efficient transcriptional complex of avian myeloblastosis virus. | a native ribonucleoprotein (rnp) complex of avian myeloblastosis virus was prepared under conditions that gave optimal cdna synthesis. the complex was an autonomous transcriptional unit capable of synthesizing dna complementary to the rna virus genome in the absence of exogenous reverse transcriptase (rna-dependent dna nucleotidyltransferase), genomic rna, and primer. the rna of the rnp complex cannot be translated in an in vitro cell-free translational system. the rnp contains intact viral rna, ... | 1980 | 6154928 |
| sequence complexity of cdna transcribed from a diverse mrna population. | mouse liver poly(a)+mrna was reverse transcribed using oligo-p(dt) or random oligonucleotides as primers to yield cdna about equal to the mass of the template rna. the size profile of the oligo-p(dt)-primedd cdna was similar to that of the template rna. rna or cdna driven saturation annealing of labeled single copy genomic dna (scdna) showed that 2% of the scdna was complementary in either case indicating the sequence complexity of cdna was equivalent to that of the template mrna. these results ... | 1980 | 6159588 |
| 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 ... | 1980 | 6159639 |
| sequence rearrangement and duplication of double stranded fibronectin cdna probably occurring during cdna synthesis by amv reverse transcriptase and escherichia coli dna polymerase i. | two cloned cdnas derived from the mrna for cell fibronectin have been sequenced, providing evidence that transcription with amv reverse transcriptase or escherichia coli dna polymerase i may not always result in double stranded cdna that is exactly homologous with its mrna template. instead, the sequences of these cloned cdnas are consistent with the duplication and rearrangement of sequences during synthesis of double stranded cdna. | 1980 | 6159581 |
| properties of the reverse transcription of synthetic and hamster retroviral rna by avian and hamster viral polymerases. | 1980 | 6155913 | |
| enzymatic synthesis of deoxyribonucleic acid by the avian retrovirus reverse transcriptase in vitro: optimum conditions required for transcription of large ribonucleic acid templates. | in this communication, we present data which describe optimum conditions for reverse transcription of large ribonucleic acid (rna) templates into deoxyribonucleic acid (dna) transcripts by the avian retrovirus reverse transcriptase in vitro. in contrast to previous studies, we have optimized all of the reaction components with respect to their influence on the size of dna transcripts rather than the incorporation of radio-labeled deoxynucleoside triphosphates into acid-insoluble dna product. the ... | 1980 | 6153530 |
| amino acid sequence analysis of reverse transcriptase subunits from avian myeloblastosis virus. | the nh(2)-terminal amino acid sequences of the alpha and beta chains of avian myeloblastosis alphabeta dna polymerase were determined by using microsequence analysis in the subnanomole range and were found to be identical up to 17 residues. the common sequence was as follows: thr-val-ala-leu-his-leu-ala-ile-pro-leu-lys-trp-lys-pro-asn-his-thr-. this result provides convincing chemical evidence that the alpha chain is derived from the nh(2)-terminal region of the beta chain by proteolytic cleavag ... | 1980 | 6160262 |
| rna primer used in synthesis of anticomplementary dna by reverse transcriptase of avian myeloblastosis virus. | when either the homologous rna (avian myeloblastosis virus rna) or a heterologous rna (poliovirus rna) was used as a template, the anticomplementary dna synthesized in vitro by avian myeloblastosis virus reverse transcriptase (rna-directed dna nucleotidyltransferase, ec 2.7.7.7) was primed by fragments of the original rna template that usually had adenosine at their 3' ends. when we used phage t/ rna ligase (ec 6.5.1.3) to label the 3' end of the rna template fragments contained in the rna . cdn ... | 1980 | 6154930 |
| purification of reverse transcriptase from avian retroviruses using affinity chromatography on heparin-sepharose. | reverse transcriptase from rous sarcoma virus and avian myeloblastosis virus was purified by a rapid two-step procedure using chromatography on phosphocellulose and heparin-sepharose. the resulting enzyme was homogeneous, had a high specific activity and was free of contaminating nucleases. this procedure has been adapted to small-scale preparation of enzyme from mutant virus containing thermolabile reverse transcriptase, and is equally suitable for large-scale enzyme purification. | 1980 | 6168644 |
| activation of an mg2+-dependent dna endonuclease of avian myeloblastosis virus alpha beta dna polymerase by in vitro proteolytic cleavage. | partial chymotryptic digestion of purified avian myeloblastosis virus alpha beta dna polymerase resulted in the activation of a mg2+-dependent dna endonuclease activity. incubation of the polymerase-protease mixture in the presence of super-coiled dna and mg2+ permitted detection of the cleaved polymerase fragment possessing dna nicking activity. protease digestion conditions were established permitting selective cleavage of beta to alpha, which contained dna polymerase and rnase h activity and ... | 1980 | 6154149 |
| 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 ... | 1980 | 6154806 |
| transcription maps of polyoma virus-specific rna: analysis by two-dimensional nuclease s1 gel mapping. | 1980 | 6154876 | |
| lactose operator--repressor interaction: use of synthetic oligonucleotides in determining the minimal recognition sequence of the lactose operator. | 1980 | 6154878 | |
| reactivity of reverse transcriptase toward (s4u,u)n copolymers and spin-labeled nucleic acid lattices. | spin-labeled copolymers of 4-thiouridine and uridine (ls4u,u)n] that contain various amounts of spin label (l) were synthesized by either (i) chemical alkylation of the 4-thiouridine-uridine copolymers (s4u,u)n prepared by copolymerizing 4-thiouridine 5'-diphosphate (s4udp) and udp or (ii) copolymerization of spin-labeled s4udp with udp using polynucleotide phosphorylase. the effect of (s4u,u)n and (ls4u,u)n on avian myeloblastosis virus (amv) rna-dependent dna polymerase (rna-dependent dna nucl ... | 1980 | 6159632 |
| inhibition of avian myeloblastosis virus reverse transcriptase by ethidium bromide: effect on enzyme activity and primer trna recognition. | 1980 | 6163656 | |
| chemical crosslinking of proteins in avian sarcoma and leukemia viruses. | 1980 | 6245502 | |
| avian oncovirus proteins expressed on the surface of infected cells. | 1980 | 6245511 | |
| isolation of complementary dna unique to the genome of avian myeloblastosis virus (amv). | 1980 | 6245521 | |
| 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 ... | 1980 | 6245172 |
| detection of viral markers and incomplete viral genome rescue from asv transformed rodent cells. | two non-virogenic rat cell lines twerc and fr transformed with pr-rsv and fsv, respectively, were analyzed. both these cell lines contained vrna, but only in twerc cells was the major viral polypeptide p27 synthetized. transforming virus can be rescued from both cell lines only after fusing them with chicken fibroblasts preinfected with avian leukosis viruses of subgroup a, c, d, f and both td mutants of pr-rsv-c and b77-c. similarly, virus was rescued in experiments in which qef infected with r ... | 1980 | 6250919 |
| 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 ... | 1980 | 6253834 |
| [morphological and virological studies on the virus cell relationship in various vertebrate cells infected with avian myeloblastosis virus (author's transl)]. | 1980 | 6257166 | |
| isolation and chemical characterization of the major envelope glycoprotein of avian myeloblastosis virus. | 1980 | 6243634 | |
| viral inhibition of lymphocyte mitogenesis. i. evidence for the nonspecificity of the effect. | we have investigated the mechanism(s) whereby virus particles, when co-incubated with lymphocytes, are able to abrogate mitogen- and alloantigen-driven cell proliferation. our data indicate that this inhibition is entirely nonspecific with regard to its induction; similar results can be obtained by using any of several different types of infectious virus particles or viruses whose infectivity had been destroyed by irradiation with ultraviolet light. furthermore, we show that plasma membranes ves ... | 1980 | 6243153 |
| target cell specificity of defective avian leukemia viruses: hematopoietic target cells for a given virus type can be infected but not transformed by strains of a different type. | defective avian leukemia viruses of the avian erythroblastosis (aev), avian myelocytomatosis (mc29), and avian myeloblastosis (amv) type induce the proliferation of leukemic cells with properties of erythroblasts, macrophages, and myeloblasts, respectively. their target cells can be separated and have properties of cells of the erythroid (aev) and myeloid lineage (mc29 and amv), respectively. in the present study we have shown that this target cell specificity is not due to the ability of the di ... | 1980 | 6244556 |
| avian retroviruses that cause carcinoma and leukemia: identification of nucleotide sequences associated with pathogenicity. | avian myelocytomatosis virus (mc29v) is a retrovirus that transforms both fibroblasts and macrophages in culture and induces myelocytomatosis, carcinomas, and sarcomas in birds. previous work identified a sequence of about 1,500 nucleotides (here denoted onc(mcv)) that apparently derived from a normal cellular sequence and that may encode the oncogenic capacity of mc29v. in an effort to further implicate onc(mcv) in tumorigenesis, we used molecular hybridization to examine the distribution of nu ... | 1980 | 6245277 |
| correlation of rna binding affinity of avian oncornavirus p19 proteins with the extent of processing of virus genome rna in cells. | we purified the p19 proteins from the prague c strain of rous sarcoma virus, avian myeloblastosis virus, b77 sarcoma virus, myeloblastosis-associated virus-2(0), and pr-e 95-c virus and measured their binding affinities for 60s viral rna by the nitrocellulose filter binding technique. the apparent association constants of the p19 proteins from rous sarcoma virus prague c, avian myeloblastosis virus, and b77 sarcoma virus for homologous and heterologous 60s rnas were similar (1.5 x 10(11) to 2.6 ... | 1980 | 6252334 |
| 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 ... | 1980 | 6247276 |
| 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 ... | 1980 | 6248880 |
| characterization of an endonuclease activity associated with friend-murine leukemia virus. | an endonuclease activity shown to be associated with friend leukemia virus has been characterized using double-stranded phi x174 dna as substrate. in the presence of mg2+, the endonuclease activity was able to convert supercoiled circular dna duplexes to the relaxed form by introducing single-stranded nicks into the dna. most of the nicked dna duplexes contained only one nick per strand, since unit length dna was the predominant species obtained when the nicked dna was analyzed by alkaline sucro ... | 1980 | 6250613 |
| isolation and translation of mrna encoded by a specific region of the herpes simplex virus type 1 genome. | we have examined in detail the major mrna species encoded by the region of the herpes simplex virus type 1 genome encoded by hindiii fragment k (0.53-0.59 from the left end of the prototype arrangement of the genome) by using this restriction fragment bound to cellulose as a reagent for isolation of this mrna. before viral dna replication in infected cells (early), a major species of viral mrna 5.2 kilobases (kb) in length is abundant. after the onset of viral dna replication (late), four mrna s ... | 1980 | 6251246 |
| progenitor-cell populations can be infected by rna tumor viruses, but transformation is dependent on the expression of specific differentiated functions. | 1980 | 6253198 | |
| 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 ... | 1980 | 6253658 |
| 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 ... | 1980 | 6253659 |
| oncogenicity of three strains of avian leukosis virus in white leghorn chicks of bk line. | 1980 | 6265807 | |
| glycoprotein and protein composition of bovine leukemia virus (blv). | highly purified preparation of bovine leukemia virus (blv) was obtained by the method described in this communication. blv was isolated from cell-free culture medium, harvested from blv-producing cell-line flk. polyacrylamide gel electrophoresis of blv proteins and glycoproteins, in comparison with avian myeloblastosis virus (amv), confirmed high purity of blv preparations. molecular weights of some blv-proteins and glycoproteins were calculated. by employing polyacrylamide gradient 5 to 30% it ... | 1980 | 6265814 |
| mutants of avian myelocytomatosis virus with smaller gag gene-related proteins have an altered transforming ability. | avian myelocytomatosis virus strain mc29 is a replication-defective avian oncovirus which in newborn chickens causes myelocytomatosis and liver and kidney tumours. in vitro infection of bone marrow cells gives rise to colonies of transformed macrophage-like cells, and cloned viruses is also capable of transforming fibroblasts. the genome of mc29 contains cellular sequences which are closely related to those in other defective leukaemia viruses with similar transforming spectra. consequently, the ... | 1980 | 6253823 |
| partial phosphorylation in vivo of the avian retrovirus pp32 dna endonuclease. | avian retrovirus pp32, a dna endonuclease which is structurally related to the avian retrovirus dna polymerase beta polypeptide, has been demonstrated to be partially phosphorylated in vivo. unlabeled or [35s]methionine-labeled pp32 from avian sarcoma virus or avian myeloblastosis virus migrated as an electrophoretic doublet on discontinuous sodium dodecyl sulfate-polyacrylamide slab gels. however, pp32 immunoprecipitated from avian sarcoma virus labeled in vivo with [32p]orthophosphoric acid mi ... | 1980 | 6257933 |
| 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 ... | 1980 | 6246269 |
| 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 ... | 1980 | 6252337 |
| 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 ... | 1980 | 6252351 |
| 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 ... | 1980 | 6254063 |
| 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 ... | 1980 | 6254077 |
| isolation of native internal structural proteins of avian oncovirions by sp-sephadex column chromatography. | 1980 | 6255957 | |
| 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 ... | 1980 | 6257200 |
| studies in amv dna. ii. a possible origin of dna present in amv virions (amv dna). | some properties of cytoplasmic nonmitochondrial dna--cyt dna--from chicken leukemic myeloblasts were determined and compared with corresponding characteristics of amv dna. our results indicate that cyt dna and amv dna molecules are akin with respect to their specific radioactivities, sedimentation behaviour and melting profiles. furthermore, the partial lack of sequence reiteration of both cyt and amv dnas distinguished them from the nuclear myeloblast dna. it is concluded that cyt dna of myelob ... | 1980 | 6257201 |
| 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 ... | 1980 | 6255923 |
| structure of and alterations to defective murine sarcoma virus particles lacking envelope proteins and core polyprotein cleavage. | htg2 hamster cells produce a defective murine sarcoma virus lacking gp70 and, consequently, viral surface projections (knobs), but the lack of knobs appears to have no effect on intramembrane particle distribution. in addition, it has been noted that the core of the virus remains in the "immature" form as a result of the failure of the polyprotein precursor (p65) to undergo cleavage. however, incubation of htg2 virus with avian myoblastosis virus was found to yield specific cleavage products of ... | 1980 | 6257930 |
| effect of actinomycin d on nucleic acid hybridization: the cause of erroneous dna elongation during dna synthesis of rna tumor viruses in vitro. | actinomycin d, known for its suppression of cellular rna synthesis and for the reduction of the rate of synthesis of double-stranded dna by the rna tumor virus rna-dependent dna polymerase, was found to interact with single-stranded dna in such a way as to inhibit dna . dna and dna . rna hybridizations. this finding is discussed in the light of the observation that dna elongation during dna synthesis of rna tumor viruses is blocked in vitro in the presence of actinomycin d. it thus supports the ... | 1980 | 6260149 |
| 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 ... | 1980 | 6255203 |
| ok10, an avian acute leukemia virus of the mc 29 subgroup with a unique genetic structure. | the rna of defective avian acute leukemia virus ok10 was isolated from a defective virus particle, released by ok10-transformed nonproducer avian fibroblasts, as a 60s complex consisting of 8.6-kilobase subunits. oligonucleotide fingerprinting and rna.cdna hybridization identified two sets of sequences in ok10 rna: group-specific sequences, which are related to all nondefective members of the avian tumor virus group, and a sequence closely related to the subgroup-specific sequences (mcv) of the ... | 1980 | 6261241 |
| 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 ... | 1980 | 6772221 |
| some circulating factors which influence granulocyte-monocyte production in the chick with myeloblastic leukemia. | soft-agar cloning was used to investigate possible granulopoietic-monopoietic regulatory defects in the chick with myeloblastic leukemia induced by avian myeloblastosis virus. the plasma levels of granulocyte-monocyte colony-stimulating activity (csa) of normal and leukemic plasmas were the same when undiluted or unfractionated plasmas were tested. however, dilution or fractionation revealed elevations in plasma csa levels in the leukemic animals. most of the activity in both normal and leukemic ... | 1980 | 6970614 |
| phenylglyoxal as a template site-specific reagent for dna and rna polymerases. selective inhibition of initiation. | phenylglyoxal, an arginine-specific reagent, strongly inhibits dna polymerases isolated from eukaryotic, prokaryotic, and rna tumor viral sources as well as escherichia coli rna polymerase. the inhibitory action of phenylglyoxal appears to be due to interference with the template binding function of these enzymes and implies the presence of an arginine residue at the template binding site of these enzymes from diverse sources and suggests that template dependent dna, and perhaps rna polymerases, ... | 1980 | 6985908 |
| the effect of nitrofurantoin on deoxyribonucleic acid synthesis in plant mitochondria. | nitrofurantoin (1-([(5-nitrofuran-2-yl)methylene]amino)imidazolidine-2,4-dione), a widely used drug and also a well-known bacterial mutagen, inhibits dna synthesis in mitochondria from 48 h etiolated seedlings of vigna sinensis (linn.) savi (snake bean). the effect appears at the level of the uptake of radioactive deoxynucleoside triphosphates by the plant mitochondria. nitrofurantoin does not inhibit dna synthesis in vitro by homogeneous escherichia coli dna polymerase i and dna polymerase from ... | 1980 | 6989360 |
| 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 ... | 1980 | 6986172 |
| [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 ... | 1980 | 7293688 |
| ontogeny of pituitary hormone mrnas in the bovine fetus. quantitation of pre-prolactin mrna as a function of gestation. | the mrna coding for pre-prolactin (pprl) of the adult bovine anterior pituitary was purified to 85% homogeneity and used as a template for cdna synthesis with reverse transcriptase from avian myeloblastosis virus. the cdna sequences complementary to pprl mrna were further purified by employing a limited back-hybridization step and treatment with s1 nuclease. the pprl cdna preparation was judged to be homogeneous by comparing its hybridization kinetics to those of ovalbumin and globin mrna standa ... | 1980 | 7380840 |
| immunopathology of chickens infected in ovo and at hatching with the avian osteopetrosis virus mav.2-0. | 1980 | 7202478 | |
| effects of ethylating agents on dna synthesis in vitro: implications for the mechanism of carcinogenesis. | a highly carcinogenic ethylating agent, ethylnitrosourea (enu), and a weakly carcinogenic one, diethylsulfate (des) react with dna to roughly the same extent but des produces about 6 times as many unstable ethylated bases, which are gradually lost spontaneously under physiological conditions. the different rates of loss for the different dna bases have been studied using polydeoxyribonucleotides. spontaneous strand breakage following base loss is slow, lagging more than a week behind base loss a ... | 1981 | 7273319 |
| 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 ... | 1981 | 7289876 |
| 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 ... | 1981 | 6941292 |
| studies on the circulating, colony-stimulatory activities in normal chicks and in chicks with myeloblastic leukemia. | 1981 | 6972320 | |
| on the fidelity of dna replication. effect of the next nucleotide on proofreading. | the contribution of proofreading to the fidelity by which escherichia coli dna polymerase i copies natural dna has been analyzed by two independent criteria. with phi x174 am 3 dna as a template, there is approximately a 25-fold increase in noncomplementary base substitutions at position 587 when the concentration of the next correct nucleotide, datp, is increased. sequence analysis indicates that the mistakes represent misincorporation of c in place of t at position 587. this mutagenic response ... | 1981 | 6456268 |
| deoxynucleoside [1-thio]triphosphates prevent proofreading during in vitro dna synthesis. | the contribution of proofreading to the fidelity of catalysis by dna polymerases has been determined with deoxyribonucleoside [1-thio]triphosphate substrates. these analogues, which contain a sulfur in place of an oxygen on the alpha phosphorus, are incorporated into dna by dna polymerases at rates similar to those of the corresponding unmodified deoxynucleoside triphosphates. the fidelity of dna synthesis was measured with phi x174 am3 dna; reversion to wild type occurs most frequently by a sin ... | 1981 | 6458818 |
| mathematical analysis of the oncornavirus maturation process (virion rna conversion and morphological condensation). | the rate of the maturation process of avian myeloblastosis virus experimentally estimated on the basis of genomic viral rna conversion and morphological transition of virions was mathematically analysed. three mathematical models were suggested and fitted to experimental data. it was found that: (a) model of simple kinetics (model 1) does not agree with experimental data. therefore, two hypotheses were considered in further mathematical modelling: (b) virions are identical in time of budding: ma ... | 1981 | 7213946 |
| influence of bursectomy on bone growth and anemia induced by avian osteopetrosis viruses. | this study examines the contribution of the bursa of fabricius to the pathogenic manifestations of two myeloblastosis-associated viruses which primarily cause osteopetrosis [mav-1(o) and mav-2(o)]. mav-2(o) infection of surgically bursectomized 1-month-old chicks resulted in a rapidly fatal anemia whereas infection of untreated chicks of the same age resulted in a transient drop in hematocrit. surgical bursectomy of embryos before or after embryonal infection with mav-2(o) did not alter the cour ... | 1981 | 6257382 |
| viral inhibition of lymphocyte mitogenesis: the role of macrophages as primary targets of virus-cell interaction. | 1981 | 6260939 | |
| duplex dna binding activity of the avian myeloblastosis virus dna polymerase. | purified avian myeloblastosis virus dna polymerase has a strong binding affinity for closed circular double-stranded dna with no 3'-hydroxy termini. because of this affinity the dna polymerase can retain labeled native cole1 dna on nitrocellulose filters. when the reaction contains four enzyme molecules per cole1 molecule about 50% of the dna is retained. higher enzyme: dna ratios cause retention of nearly 100% of the dna. the binding activity comigrates with dna synthetic activity through ion-e ... | 1981 | 6260187 |
| the genome and the intracellular rnas of avian myeloblastosis virus. | avian myeloblastosis virus (amv) is an acute leukemia virus which causes a myeloblastic leukemia in birds and transforms myeloid hematopoietic cells in vitro. we have analyzed rna from amv virions and from amv-transformed producer and nonproducer cells by gel electrophoresis followed by transfer to chemically activated paper and hybridization to several complementary dna (cdna) probes. using a cdna probe specific for amv, we identified two rna species of 7.2 and 2.3 kb, which were present in all ... | 1981 | 6260378 |
| size and genetic content of virus-specific rna in myeloblasts transformed by avian myeloblastosis virus (amv). | 1981 | 6259824 | |
| characterization of the hematopoietic target cells of aev, mc29 and amv avian leukemia viruses. | 1981 | 6258948 | |
| physical and chemical properties of the major envelope glycoprotein gp85 from avian myeloblastosis virus. | the major envelope glycoprotein gp85 of avian myeloblastosis virus, observed by electron microscopy as nearly spherical knobs projecting from the virus surface, was purified to homogeneity by gel filtration in 6 m guanidinium chloride followed by ion-exchange chromatography. the purified glycoprotein has a molecular weight of 80 000 from sedimentation equilibrium analysis. glycoprotein gp85 contains approx. 45% carbohydrate including 25% n-acetylglucosamine, while the remaining weight consists o ... | 1981 | 6263343 |
| analysis of avian myeloblastosis viral rna and in vitro synthesis of proviral dna. | two virus-specific rna species of 7.5 and 7.0 kilobases have been identified in avian myeloblastosis virus (amv) by denaturing gel electrophoresis and blot hybridization analysis, and they were found to be in a 10:1 ratio. the individual rnas direccted the cell-free synthesis of the 76,000-dalton "gag" protein and the 180,000-dalton "gal-pol" protein, thereby demonstrating 5' sequence homology of approximately 4.9 kilobases between the two species. synthesis of these two precursor proteins by th ... | 1981 | 6264460 |
| amino acid sequence of p15 from avian myeloblastosis virus complex. | the complete amino acid sequence of the p15 gag protein from avian myeloblastosis virus (amv) complex has been determined by sequential edman degradation of the intact molecule and of peptide fragments generated by limited tryptic cleavage, cleavage with staphylococcal protease, and cyanogen bromide cleavage. amv p15 is a single-chain protein containing 124 amino acids. the charged amino acids tend to be clustered in the primary structure. p15 contains a single cysteine at position 113 which may ... | 1981 | 6268146 |
| in vitro translation of avian myeloblastosis virus rna. | avian myeloblastosis virus (amv)-infected cells contain two viral mrna's, a genome-sized 34s (7.5-kilobase) mrna and a 21s (2.5-kilobase) subgenomic mrna, which contains the amv-specific sequences (myb sequences). we found that amv virions packaged both the 7.5-kilobase full-length genomic rna and the 2.5-kilobase subgenomic rna. in vitro translation of amv virion rna sized by sucrose density gradient centrifugation yielded 76,000-, 56,000-, 48,500-, 47,000-, and 32,000-dalton products. the 76,0 ... | 1981 | 6270366 |
| 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. | 1981 | 6260997 |
| accessibility of some regions of chromatin of leukemic chicken cells to single strand nuclease s1. | 1981 | 6272768 | |
| 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 ... | 1981 | 6264195 |
| differential effects of transforming avian rna tumor viruses on avian macrophages. | functionally differentiated chicken macrophages were derived by in vitro differentiation of embryonic yolk sac cells and were characterized by several macrophage-specific cell markers. uniform, infected, virus-producing cultures were obtained after exposure of these macrophages to avian myoblastosis virus (amv), avian myelocytomatosis virus (mc29), myeloblastosis-associated virus (mav-2), and prague strain of rous sarcoma virus (pr-b rsv). both amv and mc29 induced morphological transformation t ... | 1981 | 6267600 |
| proteolytic processing of avian and simian sarcoma and leukemia viral proteins. | 1981 | 6274753 | |
| cloning a cdna for the pro-alpha 2 chain of human type i collagen. | poly(a)-rna enriched for type i procollagen sequences was isolated from normal human fibroblasts and used as template to synthesize double-stranded cdna with avian myeloblastosis virus (amv) reverse transcriptase. after the ends had been blunted with nuclease s1 and dgmp tails had been added with terminal deoxynucleotidyltransferase, the double-stranded cdna was annealed with pbr322 dna that had previously been cleaved with ecori, blunted with amv reverse transcriptase, and dcmp-tailed with term ... | 1981 | 6267597 |
| 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 ... | 1981 | 6275098 |
| 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 ... | 1981 | 6275117 |
| electron microscopic characterization of avian myeloblastosis virus rna by the non-protein technique of spreading. | the quantitative analysis of the behaviour of retroviral rna (amv rna) under the conditions of the non-protein technique of electron microscopic visualization on a mono-molecular film of bac was performed. this technique resulted in visualization of intact molecules the mean length of which was 12% larger in comparison with molecules spread by the cytochrome c method. the method was found to be extremely sensitive to the surface properties of the supporting membrane which distinctly affect the s ... | 1981 | 6276235 |
| a comparison of avian and murine retrovirus polyprotein cleavage activities. | 1981 | 6263002 | |
| the artifactual nature of fluoride inhibition of reverse transcriptase and associated ribonuclease h. | 1981 | 6169342 | |
| template-binding site of amv reverse transcriptase and inactivation of the enzyme by n-ethylmaleimide. | n-ethylmaleimide, a sulfhydryl-specific reagent, strongly inhibits amv reverse transcriptase by specifically interfering with the template-binding site of the enzyme. however, the kinetics of inhibition differ widely with the composition and structure of the templates employed. the copying of templates with multiple 3'-hydroxyl termini appeared to be more susceptible to n-ethylmaleimide treatment, suggesting that the reagent may interfere with initiation of dna synthesis. the ability of a templa ... | 1981 | 6169371 |
| construction and identification of a hybrid plasmid containing dna sequence complementary to phenobarbital-inducible cytochrome p-450 messenger rna from rat liver. | cytochrome p-450 mrna has been partially purified from membrane-bound polysomes of the livers of phenobarbital-treated rats by sds-phenol-chloroform extraction, followed by poly(u)-sepharose chromatography and by centrifugation through a sucrose density gradient. cytochrome p-450 mrna activity was detected near 18s in the sucrose density gradient, accounting for approximately 5% of total mrna activity on the basis of [3h]leucine incorporation in an in vitro translation system of wheat germ. comp ... | 1981 | 6169709 |
| antiviral properties of polyinosinic acids containing thio and methyl substitutions. | polyinosinic acids containing methyl and sulphur substitutions are potent inhibitors of reverse transcriptase. substitution of sulphur for oxygen at the 6 position produces significant effects on the properties of polyinosinic acid: the kinetics of inhibition change from competitive to mixed-type and the inhibition constant falls by three orders of magnitude. in contrast, 1-methyl substitution produces no such effects. poly(1-methyl-6-thioinosinic acid) or poly(m1s6i) inhibits irreversibly, inhi ... | 1981 | 6169784 |
| [enzymatic synthesis and molecular cloning of the pigeon alpha-globin structural gene]. | double-stranded dna synthesized from the pigeon globin mrna by the subsequent actions of avian myeloblastosis virus reverse transcriptase and e. coli dna polymerase i was split with nuclease s1 and inserted into psti site in the plasmid pbr322 by poly(dg) times poly(dc) homopolymer extension technique using terminal deoxynucleotidyl transferase. e. coli transformants have been shown to contain pigeon globin sequences by colony hybridization with pigeon globin [32p]cdna. the inserted dna fragment ... | 1981 | 6172703 |
| inhibition of reverse transcriptase by tyrosinase generated quinones related to levodopa and dopamine. | several derivatives of levodopa have been shown to be potent inhibitors of the sulfhydryl enzyme, rna dependent dna polymerase, reverse transcriptase (rt). in the presence of the polyphenol oxidase, tyrosinase, the inhibitory values were between 10(-6) m and 10(-5) m. structure-activity studies revealed that active oxidation or reduction was necessary for this potent inhibitory response. spectrophotometric analysis showed that the presence of both the quinone and quinol was required for maximum ... | 1981 | 6173137 |
| inability of avian myeloblastosis virus rna-directed dna polymerase to transcribe poly(ru) due to instability of the oligo(da): poly(ru) complex. | 1981 | 6174121 | |
| effect of heme on globin messenger rna synthesis in spleen erythroid cells. | synthesis of globin mrna in erythroid spleen cells from anemic mice was measured after in vitro incubation under conditions in which the level of intracellular heme was manipulated. this newly synthesized globin mrna was isolated by hybridization with globin cdna covalently bound to cellulose. isonicotinic acid hydrazide (inh) and penicillamine were used as specific inhibitors of heme synthesis. it has been found that a 120-min incubation of spleen erythroid cells with 5mm inh or 5mm penicillami ... | 1981 | 6166793 |
| effect of atp on the friend murine leukemia virus-associated endonuclease activity and the endonuclease activity of the avian myeloblastosis virus rna-directed dna polymerase. | the mn2+-dependent endonuclease activity associated with the avian myeloblastosis virus rna-directed dna polymerase has been shown to be activated by atp in the presence of mg2+. in the presence of mn2+ the endonucleolytic activity was stimulated about 3-fold by the addition of atp. the earlier identified mr = 40,000 friend murine leukemia virus (f-mulv)-associated endonuclease which functions in the presence of both mg2+ and mn2+ has also been shown to be similarly stimulated by atp. for both e ... | 1981 | 6167571 |
| sites of termination of in vitro dna synthesis on ultraviolet- and n-acetylaminofluorene-treated phi x174 templates by prokaryotic and eukaryotic dna polymerases. | in vitro dna synthesis on a phi x174 template primed with a restriction fragment and catalyzed by the escherichia coli dna polymerase i large (klenow) fragment (pol i) terminates at the nucleotide preceding a site that has been altered by ultraviolet irradiation or treatment with n-acetylaminofluorene. termination on ultraviolet-irradiated templates is similar when synthesis is catalyzed by e. coli dna polymerase iii holoenzyme (pol iii), phage t4 dna polymerase, a polymerase alpha from human ly ... | 1981 | 6165985 |
| virus-coded dna endonuclease from avian retrovirus. | reverse transcriptase from avian retrovirus has a physically associated dna endonuclease with novel substrate and cofactor requirements. a similar endonuclease activity copurifies with pp32, a protein from viral cores that has been identified with the non-alpha region of the beta subunit of reverse transcriptase. several temperature-sensitive mutants of avian retrovirus with thermolabile dna polymerase were tested for thermal sensitivity of their dna endonuclease activity. two pol mutants of rou ... | 1981 | 6165835 |
| mechanism of action of moloney murine leukemia virus rna-directed dna polymerase associated rnase h (rnase h i). | the mechanism of action of the ribonuclease h (rnase h) activity associated with moloney murine leukemia virus rna-directed dna polymerase (rnase h i) and the two-subunit (alpha beta) form of avian myeloblastosis virus dna polymerase were compared by utilizing the model substrate (a)n.(dt)n and polyacrylamide gel electrophoresis in 7 m urea to analyze digestion products. examination on 25% polyacrylamide gels revealed that a larger proportion of the rnase h i oligonucleotide products generated b ... | 1981 | 6162482 |