Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| properties of the avian viral protein p12. | the avian rna tumour virus structural protein p12 was purified from avian myeloblastosis virus (amv) by nucleic acid affinity chromatography to apparent homogeneity as judged from sds--polyacrylamide gel electrophoresis. a filter binding assay was used for the identification of p12. high concentrations of p12 precipitated nucleic acids out of solution in the absence of mgcl2. binding of p12 to single-stranded nucleic acids protected them from digestion with nucleases and resulted in a hyperchrom ... | 1981 | 6169796 |
| molecular cloning of complementary dna to swine pepsinogen mrna. | poly(a)-containing rna was isolated from total rna of swine gastric mucosa by oligo(dt)-cellulose chromatography, and was translated in a wheat germ cell-free system. analysis of the translation products by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that pepsinogen was a major translation product and was synthesized as two different molecular forms with apparent molecular weights of 45,000 and 43,000. the pepsinogen translated in the in vitro translation system had no aut ... | 1981 | 6170644 |
| [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 |
| preparation of cdna, ds cdna, and tailed ds cdna from interferon mrna templates. | 1981 | 6173719 | |
| 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 | |
| enzymatic synthesis of duplex dna by avian myeloblastosis viral reverse transcriptase. | 1981 | 6086036 | |
| evidence for the absence of swelling of alfalfa mosaic virions. | the stability of the quaternary structure of bottom and top components of alfalfa mosaic virus (respectively amv-b and amv-ta-t) in the ph range 5.5 to 7.8 and at ionic concentrations of 0.01 and 0.1 m has been investigated using small-angle x-ray scattering and photon correlation spectroscopy. the x-ray scattering curves show no significant changes over the angular range measured (to a resolution of 1 100 a (-1)) under the various solvent conditions; the radius of gyration of amv-ta-t is consta ... | 1981 | 18635037 |
| lack of serological relationship between the 35k nonstructural protein of alfalfa mosaic virus and the corresponding proteins of three other plant viruses with a tripartite genome. | alfalfa mosaic virus rna 3 was translated in the mrna-dependent rabbit reticulocyte cell-free system. the 35k translational protein was partly purified and used to raise antibodies. the antibodies obtained reacted with the 35k protein directed by amv rna 3 but not with the corresponding proteins directed by rnas from three other viruses with a tripartite genome (tobacco streak, cucumber mosaic, and brome mosaic). | 1981 | 18635042 |
| evidence that alfalfa mosaic virus infection starts with three rna-protein complexes. | the tripartite genome of alfalfa mosaic virus (amv) needs to be activated by its coat protein. to establish whether coat protein exerts its role by interacting structurally with one, two, or all three amv-rna species, the infectivity of mixtures of rna-protein complexes with free rnas were studied (smit and jaspars, virology 104, 454-461, 1980). these studies were not fully conclusive since some redistribution of coat protein does occur as soon as rnas are brought into contact with rna-protein c ... | 1981 | 18635065 |
| homology in the 3'-terminal regions of different barley stripe mosaic virus rna species. | preparations of [3h]dna complementary to the individual species of barley stripe mosaic virus (bsmv) rna (cdna) about 1000 nucleotides long were obtained using avian myeloblastosis virus reverse transcriptase and oligo(dt)10 primer. these cdnas were used in kinetic hybridization experiments to study the sequence homology between the 3'-terminal regions (not including 150-200 nucleotides adjacent to the 3'-end) of individual bsmv rna species. these regions in rna 2 and 3 are highly homologous and ... | 1981 | 18635081 |
| molecular cloning of the complementary dna copies of the common and cowpea strains of tobacco mosaic virus rna. | complementary dna (cdna) copies of the common (om) and cowpea (cc) strains of tobacco mosaic virus (tmv) rna polyadenylated in vitro have been synthesized with amv reverse transcriptase and oligo (dt)10 as primer. the cdna was converted to a double-stranded form by e. coli dna polymerase i followed by s1 nuclease digestion. the double-stranded cdna copies were cloned in pbr322 at the psti site using the oligo(dc)-oligo(dg) tailing method. with the common strain, several clones containing inserts ... | 1982 | 18635128 |
| detection of avian leukosis virus with the elisa system: evaluation of conjugation methodology and comparison of sensitivity with the phenotypic mixing test in commercial layer flocks. | conjugates of horseradish peroxidase with rabbit igg antibody against gs antigen (p27) of avian myeloblastosis virus were prepared using glutaraldehyde and periodate methods of coupling. conjugates were evaluated for the detection of gs antigen of avian leukosis and sarcoma viruses in the elisa system and the periodate conjugate was found to be superior. with an elisa based on a periodate conjugate it was possible to detect 5 x 10(3) iu of leukosis virus propagated in cell culture. comparisons b ... | 1982 | 18770224 |
| a colony hybridization study of mrna in maturating soybean seeds. | polysomal poly(a)rna was transcribed by avian myeloblastosis virus (amv) reverse transcriptase and double-stranded complementary dna (cdna) was then synthesized and cloned in escherichia coli c600 by (dg)-(dc) tailing in the psti site of pbr322. a bank of mrna sequences from maturating soybean seeds (average weight 200 mg) was obtained. (32)p-cdna based on mrna from various organs of the plant (leaves, axes, seeds) was synthesized. the clones were hybridized with different kinds of (32)p-cdna on ... | 1982 | 24257772 |
| the synthesis of dna complementary to polyadenylate-containing rna from bacillus subtilis. | we had shown earlier (gopalakrishna, y., langley, d., sarkar, n. (1981) nucleic acid res. 9, 3545-3554) that a substantial fraction of mrna of various bacterial species carries 3'-terminal polyadenylate sequences. in this paper, we show that poly(a)-containing rna from bacillus subtilis can serve as template for the synthesis of complementary dna by avian myeloblastosis virus reverse transcriptase, provided that oligodeoxythymidylate is added as primer. poly(a)-rna purified by affinity chromatog ... | 1982 | 6174511 |
| reverse transcription of avian myeloblastosis virus 35s rna. early synthesis of plus strand dna of discrete size in reconstructed reactions. | the early dna products of reverse transcription have been analyzed from reconstructed reactions containing avian myeloblastosis virus 35s rna . trnatrp complex and highly purified reverse transcriptase. we describe conditions for the synthesis of genome-length complementary dna and two discrete species of plus strand dna (the same chemical polarity as the viral rna genome) about 300 and 400 nucleotides in length. plus dna400 and plus dna300 were detected by molecular hybridization with dna probe ... | 1982 | 6174940 |
| 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 ... | 1982 | 6175623 |
| reverse transcriptase associated with avian sarcoma-leukosis viruses. ii. comparison of subunit structure and catalytic properties. | the three enzyme forms (alpha, alpha beta-, and beta-form) of the rna-dependent dna polymerase (the reverse transcriptase) from three strains of avian sarcoma virus (asv b77, asv tsla334, and asv qv2) and one exogenous (avian myeloblastosis virus (amv)) and one endogenous avian leukosis virus (rous-associated virus type-0 (rav-0) were compared with each other in subunit structure and catalytic properties. despite the gross similarity in the subunit molecular weight (mr(alpha) = 65,000 and mr(bet ... | 1982 | 6175624 |
| binding of nucleotide spin probes to amv reverse transcriptase and metal ions. | 1982 | 6176469 | |
| differential inhibition of dna polymerase and rnase h activities of the reverse transcriptase by phosphonoformate. | three potential inhibitors of reverse transcriptase activities, phosphonoformate (pf), phosphonoacetate (paa), and ethyl-diethyl phosphonoformate (et-pf), were compared in this study. only pf was found to inhibit the dna polymerase activity of the purified reverse transcriptase of moloney murine leukemia virus (m-mulv) and avian myeloblastosis virus (amv). the degree of dna polymerase inhibition was linear with pf concentration; 50% inhibition was achieved at 10 mum. whereas pf inhibited both th ... | 1982 | 6178013 |
| stereochemical course of polymerization catalyzed by avian myeloblastosis virus reverse transcriptase. | the sp diastereomer of thymidine 5'-o-(1-thiotriphosphate) was polymerized by avian myeloblastosis virus reverse transcriptase using poly(a) . d(pt)10 as template-primer. degradation of the template poly(a) by alkaline hydrolysis and isolation by gel chromatography gave a single-stranded poly(d(p(s)t)), a polymer of thymidine 5'-phosphorothioate. to determine the configuration of the phosphorothioate internucleotide linkage, this material was degraded by snake venom phosphodiesterase. comparison ... | 1982 | 6178737 |
| 5-mercaptopolyuridylic acid (mpu), a potent inhibitor of the reverse transcriptase from avian myeloblastosis virus. | the effects of partially thiolated polyuridylic acid (mpu), partially thiolated polycytidylic acid (mpc), and their unmodified counterparts, poly(u) and poly(c), respectively, on the reverse transcriptase of avian myeloblastosis is virus (amv) have been determined, using different template-primers. poly(c) stimulated and mpc inhibited the polymerization reaction catalyzed by the amv reverse transcriptase in the presence of the natural viral template (endogenous rna or purified 70s rna), or with ... | 1982 | 6179137 |
| inhibition of reverse transcriptase activity of avian myeloblastosis virus by pyrophosphate analogues. | several pyrophosphate analogues have been studied for their effects on avian myeloblastosis virus reverse transcriptase and on cellular dna polymerase alpha. examination of structure-activity relationships for these compounds revealed that two acidic groups connected by a short bridge were necessary, but not sufficient, for inhibition of the enzyme activities. foscarnet sodium (trisodium phosphonoformate) was the most potent inhibitor of reverse transcriptase, giving non-competitive inhibition o ... | 1982 | 6179470 |
| mechanism of linear dna circularization: formation of 'lasso'-like structures of pre-mrna dna copies. | an electron microscopic investigation of a dna product synthesized on the pre-mrna template using amv reverse transcriptase in the absence of actinomycin d revealed linear single-stranded and double-stranded molecules, and, also, double-stranded branched as well as 'lasso'-like and circular structures. models for the formation of such dna structures are proposed. | 1982 | 6181388 |
| rose bengal mediated inhibition of dna polymerases: mechanism of inhibition of avian myeloblastosis virus reverse transcriptase under nonoxidative conditions. | 1982 | 6182904 | |
| interactions between dna polymerase and aminofluorene adducts that affect the recognition and possibly the mutagenicity of the lesions. | adducts of 2-aminofluorene on the c-8 position of guanine block dna synthesis and lead to mutation. n-acetylated adducts adopt the syn conformation such that in dna the guanine is displaced from the helix by the fluorene ring while unacetylated adducts prefer the anti conformation allowing normal base pairing of the guanine with cytosine. in vitro synthesis by both e. coli dna polymerase i and t4 dna polymerase terminates predominantly one nucleotide before acetylated adducts but has an increase ... | 1982 | 6182925 |
| antibodies to reverse transcriptase of avian oncoviruses in sera of specific-pathogen-free chickens. | 1982 | 6183954 | |
| 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 ... | 1982 | 6184143 |
| inhibition of avian myeloblastosis virus reverse transcriptase and virus inactivation by metal complexes of isonicotinic acid hydrazide. | the cupric and ferric complexes of isonicotinic acid hydrazide (inh) inhibit the dna synthesis catalysed by avian myeloblastosis virus (amv) reverse transcriptase. the inhibition was to the extent of 95% by 50 microm of cupric-inh complex and 55% by 100 microm of ferric-inh complex. these complexes have been found to bind preferentially to the enzyme than to the template-primer. kinetic analysis showed that the cupric-inh complex is a non-competitive inhibitor with respect to dttp. the time cour ... | 1982 | 6185090 |
| avian myeloblastosis reverse transcriptase deacylates tryptophanyl-trna. | tryptophanyl-trna can be used as a primer for rna-dependent dna synthesis by avian reverse transcriptase. we have determined that whereas the retroviral polymerase is not by itself capable of deacylating trp-trnatrp, the ester linkage between the 3' oh of the ribose moiety and the aminoacid can be very efficiently hydrolyzed when both the polymerase and the viral 35 s rna are present. | 1982 | 6185923 |
| effect of acetylated and deacetylated 2-aminofluorene adducts on in vitro dna synthesis. | we have constructed primed phi x174 dna templates containing either acetylated or deacetylated aminofluorene adducts at the c-8 position of guanine. t4 dna polymerase terminates synthesis one nucleotide before the acetylated adducts but incorporates an additional nucleotide opposite the deacetylated guanylaminofluorene. these observations can be explained by the known preferred conformations of the acetylated and deacetylated guanosinylaminofluorene nucleosides--the former favoring the syn confo ... | 1982 | 6185946 |
| tandemly repeated hexanucleotide at tetrahymena rdna free end is generated from a single copy during development. | the linear extrachromosomal ribosomal dna of tetrahymena is generated from a single integrated copy during macronuclear development. the free ends of this extrachromosomal gene contain 20-70 tandem repeats of the hexanucleotide ccccaa. we have determined the nucleotide sequence at the same (3') end of the single, integrated micronuclear gene. in contrast to the extrachromosomal gene, only a single ccccaa sequence was found at this position. the same result was obtained from two independently iso ... | 1982 | 6186380 |
| synthesis of full-length cdnas from partially purified human procollagen mrnas. | partially purified human procollagen mrnas have been copied using reverse transcriptase from avian myeloblastosis virus. under standard conditions, using a high deoxynucleotide concentration, only incomplete cdnas corresponding to one-fifth to one-half of the template could be synthesized. addition of a ribonuclease inhibitor from human placenta in the reaction mixture allowed the synthesis of full-length cdna copies from extremely long procollagen mrna. | 1982 | 6186901 |
| studies on the structure of avian myeloblastosis virus (amv) rna. i. factors affecting electron microscopic visualization of amv rna. | factors affecting the visualization of single-stranded (ss) avian myeloblastosis virus (amv) rna by the basic protein film technique under strong denaturation conditions were studied. the basic parameters of the electron microscopic picture of ss rna, involving the visibility, concentration and contour lengths of molecules, were found to be significantly dependent on the (1) quality of denaturing components used for full extension of amv rna molecules and (2) spreading and formation of the surfa ... | 1982 | 6124101 |
| 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 ... | 1982 | 6124106 |
| studies on the structure of avian myeloblastosis virus (amv) rna. iii. electron microscopic definition of secondary structure. | the secondary structure of avian myeloblastosis virus (amv) rna was characterized by electron microscopy under moderately denaturing spreading conditions. under denaturation by aqueous 44% formamide or 77% formamide in the presence of salts, partly stretched rna molecules with measurable double-stranded regions were observed. this approach allowed the localization from 5 to 11 regions of preserved secondary structure on amv rna molecules. topographic analysis revealed a nonrandom occurrence of s ... | 1982 | 6124107 |
| electron microscopic studies on the structure of 60-70s rna of avian myeloblastosis virus. | structural properties of the 60-70s rna complex of avian myeloblastosis virus (amv) were analysed in electron microscope after treatment under a set of non-denaturing, gently and strongly denaturing conditions. by selected denaturing conditions, the significant fraction of 60-70s amv rna molecules revealed partially unfolded structures either in a dimer or a more complex form and in a length corresponding to mol. wt. of 5.6 x 10(6). the typical dimers contained a characteristic central structure ... | 1982 | 6132536 |
| studies on the function of the non-primer trnas associated with the 70 s rna of avian myeloblastosis virus. | significant amounts of three trnas are associated with the 70 s rna of avian myeloblastosis virus (amv). the temperatures at which they are half dissociated from the 70 s rna in 50 mm nacl and their respective quantities relative to 35 s rna are: trnaarg, 51 degree c, 1.6; trnalys, 57 degree c, 0.7 and trnatrp, 76 degree c, 1.0. possible functions for the non-primer trnas (trnaarg and trnalys) were evaluated by determining the effect of their thermal dissociation on: (a) conversion of 70 s to 35 ... | 1982 | 6277384 |
| helper viruses associated with avian acute leukemia viruses inhibit the cellular immune response. | 1982 | 6278717 | |
| the effects of t-cell growth factor and virus purification on virus-mediated inhibition of lymphocyte mitogenesis. | many different types of virus particles are able to non-specifically impede the ability of human peripheral blood lymphocytes to respond to mitogenic ro alloantigenic stimuli. this result is not obtained if ultra-purified virus is employed, although virus which has been banded only once through sucrose generally retains inhibitory potential. ultra-pure virus is relatively unable to bind to cell surfaces, suggesting the importance of physical contact between viruses and cells in order for the obs ... | 1982 | 6282509 |
| 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 ... | 1982 | 6282836 |
| 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- ... | 1982 | 6283118 |
| 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 ... | 1982 | 6283142 |
| nucleotide sequence of the transforming gene of avian myeloblastosis virus. | avian myeloblastosis virus is defective in reproductive capacity, requiring a helper virus to provide the viral proteins essential for synthesis of new infectious virus. this virus arose by recombination of the nondefective helper virus and host cellular sequences present within the normal avian genome. these latter sequences are essential for leukemogenic activity. the complete nucleotide sequence of this region is reported. within the acquired cellular sequences there is an open reading frame ... | 1982 | 6283631 |
| biological activity of proviral dna isolated from cells infected with mav-2(0) virus. | the ability of dna isolated from avian myeloblastosis-associated virus mav-2(0)-infected fibroblasts to induce the synthesis of virus upon transfection of susceptible but not resistant cells was demonstrated. the virus obtained, when inoculated into 12-day-old embryos, led to the manifestation of osteopetrosis after prolonged incubation and to the induction of nephroblastomas in some cases. positive transfection with dna from the non-virus producing myeloblast cell line was not detected on bone ... | 1982 | 6284559 |
| avian nephroblastoma virus mav-2(n) and avian osteopetrosis virus mav-2(o) are genetically distinct. | avian myeloblastosis virus consists of a mixture of a defective leukaemia virus and several non-defective associated avian leukosis viruses. the genomes of two of the associated avian leukosis viruses were examined in this study and were chosen because one of them, mav-2(n), induces predominantly nephroblastoma, while the other, mav-2(o), induces predominantly osteopetrosis. competitive hybridization studies employing labelled virion rna and dna from normal and malignant tissue failed to demonst ... | 1982 | 6284866 |
| nucleotide sequence analysis of the long terminal repeat of avian myeloblastosis virus and adjacent host sequences. | the nucleotide sequence of the integrated avian myeloblastosis virus long terminal repeat has been determined. the sequence is 385 base pairs long and is present at both ends of the viral dna. the cell-virus junctions at each end consist of a 6-base-pair direct repeat of cell dna next to the inverted repeat of viral dna. the long terminal repeat also contains promoter-like sequences, an mrna capping site, and polyadenylation signals. several features of this long terminal repeat suggest a struct ... | 1982 | 6284999 |
| isolation of the major envelope glycoprotein of avian myeloblastosis virus. | 1982 | 6285134 | |
| 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 ... | 1982 | 6285358 |
| in vitro processing of avian oncovirus precursor polypeptide pr76gag by virion protein p15. | in vitro cleavage by p15 virion protein of the primary translation product of the avian oncovirus gag gene, the precursor polypeptide pr76gag, was studied in kinetic experiments. nondenatured 35s-methionine-labelled pr76gag, which was synthetized in reticulocyte lysate programmed by genomic amv-rna was used as a substrate, pure native p15 (amv) as a protease. reaction conditions were optimal for in vitro protein synthesis. composition of the cleavage products was estimated by immune precipitatio ... | 1982 | 6286372 |
| 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 ... | 1982 | 6286858 |
| a comparison of the mobilities and thermal transitions of retrovirus lipid envelopes and host cell plasma membranes by electron spin resonance spectroscopy. | the lipid bilayers of several type-c retroviruses and selected host cells were spin labeled with 5-doxyl stearic acid, and intact viruses and cells were subjected to electron spin resonance spectroscopy in order to measure lipid mobility. thermal transition profiles generated for four different retroviruses were dissimilar; differences in the values of the hyperfine splitting constant 2t parallel and in the positions of thermal break points reflect variations in mobility which can be correlated ... | 1982 | 6288099 |
| nuclear location of the putative transforming protein of avian myelocytomatosis virus. | the putative transforming protein of avian myelocytomatosis virus mc29 is a 110,000 dalton (p110gag-myc) polyprotein comprised of sequences derived from both the gag region and the mc29-specific myc region. two approaches have been taken to determine the location of the mc29 gag-related proteins in transformed cells: subcellular fractionation and immunofluorescence. analysis of subcellular fractions of mc29-transformed cells by immunoprecipitation indicates that the majority of the gag-myc polyp ... | 1982 | 6288259 |
| chromosomal assignment of the human homologues of feline sarcoma virus and avian myeloblastosis virus onc genes. | retroviral transforming genes, v-onc genes, are derived from normal cellular sequences that are called cellular onc (c-onc) genes. dna from mouse-human somatic cell hybrids that have selectively lost human chromosomes was used in southern blots to map the chromosomal location of two human onc genes. cloned human homologues of retroviral onc genes were used as probes. because the human c-fes gene, which is homologous to feline sarcoma virus, segregates concordantly with human chromosome 15, and t ... | 1982 | 6289315 |
| virion dna of ground squirrel hepatitis virus: structural analysis and molecular cloning. | the structure of the encapsidated dna genome of ground squirrel hepatitis virus (gshv) has been examined by restriction endonuclease cleavage, nucleic acid hybridization, and molecular cloning. gshv virion dna is a relaxed circular molecule of approximately 3,200 bases in length; most molecules harbor an extensive single-stranded region which is largely confined to one-half of the genome. the full-length viral dna strand is covalently bound to protein. the single-stranded region can be repaired ... | 1982 | 6292498 |
| 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 ... | 1982 | 6292502 |
| 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. | 1982 | 6292519 |
| nucleotide sequence of the retroviral leukemia gene v-myb and its cellular progenitor c-myb: the architecture of a transduced oncogene. | the oncogene (v-myb) of avian myeloblastosis virus and a large portion of its cellular homolog (c-myb) have been molecularly cloned and sequenced. the portion of c-myb we analyzed contains seven interspersed segments (or exons). fusion of these exons creates a continuous nucleotide sequence that is remarkably similar to the sequence of v-myb and that potentially encodes a protein very similar to that specified by v-myb. comparisons between the sequences of v-myb and c-myb indicate that transduct ... | 1982 | 6297766 |
| 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 ... | 1982 | 6297778 |
| site-specific mutagenesis by error-directed dna synthesis. | 1982 | 6460194 | |
| inhibition of concanavalin a response during osteopetrosis virus infection. | infection of animals with oncogenic viruses frequently leads to an immunosuppressed state. we have examined immunosuppression induced by an avian osteopetrosis virus, myeloblastosis-associated virus of subgroup b inducing osteopetrosis [mav-2(o)], and our results suggest that this virus induces immunosuppression by a novel mechanism. lymphoid cells from osteopetrotic chickens did not respond to a wide dose range of concanavalin a (con a) over a wide cell density range. failure to undergo blastog ... | 1982 | 6213295 |
| in vitro replication of mutagen-damaged dna: sites of termination. | we have examined the effect of dna lesions, which in vivo are potentially mutagenic, on in vitro dna synthesis carried out by a number of purified dna polymerases using a 0x174 template. both acetyl aminofluorene (aaf) adducts and uv-induced pyrimidine dimers are blocks to elongation by dna polymerases. on uv-irradiated dna templates synthesis terminates one nucleotide before the sites of pyrimidine dimers with all of the enzymes tested: pol i and pol iii holoenzyme from escherichia coli, t4 dna ... | 1982 | 6214248 |
| 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 ... | 1982 | 6954533 |
| 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 ... | 1982 | 6978259 |
| disintegration of retroviruses by chelating agents. | exposure in vitro of various mammalian retroviruses to the chelating agents edta or egta in millimolar concentrations resulted in partial disintegration of viral membranes as measured by accessibility or even release of reverse transcriptase, an internal viral protein, without any other treatment usually required. among the viruses responding to chelators were mammalian type c viruses, primate type d viruses and bovine leukemia virus. the effect was dose-dependent. the avian type c virus amv, ho ... | 1982 | 6816193 |
| 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 ... | 1982 | 7040433 |
| cell oncogenes are located on the large microchromosomes in chicken cells. | 1982 | 7064350 | |
| dna polymerase and thymidine kinase activities in mc-29 virus-induced transplantable hepatoma and the effect of cytostatic treatment of these activities. | the activity of dna polymerases and thymidine kinase was compared in the mc-29 leukosis virus-induced transplantable hepatoma and in the livers of rats treated with cyclophosphamide (cp), cytosine-arabinoside (ara-c) and 5-fluoro-uracil (5-fu). the specific activity of dna polymerase was twenty times greater in the mc-29 leukosis virus-induced hepatoma, while thymidine kinase was only 3-5 times greater than in liver. all three enzymes showed michaelis-menten kinetics in their substrate and templ ... | 1982 | 7105249 |
| isolation and characterization of retrovirus-like elements from normal human fetuses. | retrovirus-like particles have been isolated from normal fetal human plasma and from different embryonic organs collected from late first-trimester fetuses. the majority of the virus-like particles banded at a density region of of 1.19-1.22 g/ml, although lighter particles having a density of 1.15-1.17 g/ml were observed in some fetal tissues. the particles appeared similar to retroviruses when viewed electron-microscopically. they contained reverse transcriptase (rt) which accepted oligo (dg)-p ... | 1982 | 7129678 |
| translational competition between related virus rna species in cell-free systems. | the competition between the rnas from two tobacco mosaic virus (tmv) strains for translation in rabbit reticulocyte lysate and wheat germ cell-free systems was investigated. the virus translational products were distinguished by the size difference of the i2 polypeptides. the rnas of the two strains were translated simultaneously if added to the translation system together at the beginning of the reaction. each of the tmv rnas could inhibit translation of the other when the reaction was initiate ... | 1982 | 7142974 |
| mouse c-myc oncogene is located on chromosome 15 and translocated to chromosome 12 in plasmacytomas. | hybridization studies with viral oncogene probes indicate that c-myc, the cellular gene homologous to the transforming gene of avian myelocytomatosis virus, resides on mouse chromosome 15 and in many plasmacytomas is translocated to the antibody heavy chain gene locus on chromosome 12. the transcriptional orientation of the translocated c-myc sequence is opposite the orientation of the adjacent c alpha gene that codes for the heavy chain of immunoglobulin a. the translocated c-myc sequence is no ... | 1982 | 7146913 |
| 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 ... | 1982 | 6302112 |
| 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 ... | 1982 | 6302118 |
| avian osteopetrosis. | 1982 | 6303704 | |
| modulation of atpase activity of avian myeloblastosis virus with ca2+, atp & its reaction products. | 1982 | 6299931 | |
| 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 ... | 1982 | 6329725 |
| characterization of the expression of cellular retrovirus genes and oncogenes in feline cells. | expression of endogenous retrovirus genes and two different cellular oncogenes (c-onc genes) was examined at the transcriptional level in a variety of normal and lymphoma/leukemia tissues of the domestic cat. the two oncogenes, c-myb(related to avian myeloblastosis virus) and c-myc(related to avian myelocytomatosis virus) were selected for their association with the induction of hematopoietic malignancies, when present in the transforming retroviruses. tissue-specific expression of endogenous fe ... | 1983 | 6329934 |
| depurination-induced infidelity of deoxyribonucleic acid synthesis with purified deoxyribonucleic acid replication proteins in vitro. | removal of purine bases from phi x174 single-stranded dna leads to increased reversion frequency of amber mutations when this dna is copied in vitro with purified dna polymerases. this depurination-induced mutagenesis is observed at three different genetic loci and with several different purified enzymes, including escherichia coli dna polymerases i and iii, avian myeloblastosis virus dna polymerase, and eukaryotic dna polymerases alpha, beta, and gamma. the extent of mutagenesis correlates with ... | 1983 | 6344919 |
| simple construction of human c-myc gene implicated in b-cell neoplasmas and its relationship with avian v-myc and human lymphokines. | 1983 | 6359370 | |
| rna-protein interactions in some small plant viruses. | the structure of the three quasi-equivalent protein subunits a, b and c of the spherical, t = 3 southern bean mosaic virus (sbmv) have been carefully built in accordance with a refined electron density map of the complete virus. the lower electron density in the rna portion of the map could not be explicitly interpreted in terms of a preferred rna structure on which some icosahedral symmetry might have been imposed. however, the extremely basic nature of the interior surface of the coat protein ... | 1983 | 6401119 |
| synthesis of thymosin alpha 1 precursor cdna and purification of active mrna by affinity chromatography. | 1. thymosin alpha 1 precursor [3h]cdna-cellulose synthesis was carried out by reverse transcription with rna-dependent dna polymerase from avian myeloblastosis virus using oligo(dt)-bound to cellulose as a primer. 2. unlabelled thymosin alpha 1 precursor cdna-cellulose was synthetized in a preparative scale to be used in affinity chromatography. 3. poly(a)-mrna from calf thymus was subjected to cdna-cellulose affinity chromatography and an active messenger obtained in a yield of 3% respect to th ... | 1983 | 6401638 |
| control of tyrosinase gene expression and its relationship to neural crest induction in rana pipiens. ii. measurement of tyrosinase mrna accumulation during early embryogenesis using a specific cdna probe. | the relationship between the process of neural induction and the control of tyrosinase gene expression in the cells that derive from the neural crest of amphibians has been examined at the molecular level. [3h] tyrosinase cdna was utilized as a probe to measure the levels of tyrosinase rna transcripts present in rana pipiens embryos from the time of fertilization through stage 25 of cleavage (operculum complete, 240 h) and to correlate these levels with those published for the rate of tyrosinase ... | 1983 | 6418741 |
| purification and properties of a fifth major viral gag protein from avian sarcoma and leukemia viruses. | we have developed procedures for the purification of a 6,000-dalton protein from avian myeloblastosis virus. this protein is a major component of avian myeloblastosis virus, accounting for over 7% of total protein, and thus is equimolar with the other internal structural proteins in virions. as described in the accompanying paper (hunter et al., j. virol. 45:885-888, 1983), the results of n-terminal amino acid sequence analysis identify the protein as a product of the gag gene. we suggest denoti ... | 1983 | 6300427 |
| cyanogen bromide digestion of the avian myeloblastosis virus pp19 protein: isolation of an amino-terminal peptide that binds to viral rna. | the avian myeloblastosis virus pp19 protein was separated from the other virus proteins by a rapid and simple purification procedure which yields milligram amounts of homogeneous protein. this protein was then fragmented by digestion with cyanogen bromide. when the mixture of the cyanogen bromide peptides was passed through a 60s avian myeloblastosis virus rna-cellulose column, only one peptide bound with high affinity to the resin. the peptide migrated on a sodium dodecyl sulfate-polyacrylamide ... | 1983 | 6300441 |
| amino-terminal amino acid sequence of p10, the fifth major gag polypeptide of avian sarcoma and leukemia viruses. | we have identified p10 as a fifth gag protein of avian sarcoma and leukemia viruses. amino-terminal protein sequencing of this polypeptide purified from the prague c strain of rous sarcoma virus and from avian myeloblastosis virus implies that it is encoded within a stretch of 64 amino acid residues between p19 and p27 on the gag precursor polypeptide. for p10 from the prague c strain of rous sarcoma virus the first 30 residues were found to be identical with the predicted amino acid sequence fr ... | 1983 | 6300442 |
| 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 ... | 1983 | 6300463 |
| infidelity of dna synthesis associated with bypass of apurinic sites. | the mutagenic potential of apurinic sites in vivo has been studied by transfection of depurinated phi x174 dna containing amber mutations into sos-induced escherichia coli spheroplasts. mutagenicity is abolished by treatment of the depurinated dna with an apurinic endonuclease from hela cells, establishing the apurinic site as the mutagenic lesion. the frequency of copying apurinic sites in vitro was analyzed by measuring the extent of dna synthesis using e. coli dna polymerase i and avian myelo ... | 1983 | 6300848 |
| avian myeloblastosis virus: a model for the generation of viral oncogenes from potentially oncogenic cellular genetic elements. | 1983 | 6301896 | |
| amphiphilic properties of the avian myeloblastosis virus major glycoprotein, gp 80. | the major glycoprotein (gp 80) from avian myeloblastosis virus (amv) displays significant lipophilic properties, as shown by its strong interactions with acetylated uncharged decylamino agarose in hydrophobic chromatography. in effect, release from binding was achieved only by the added presence of a polarity reducing agent (ethylene glycol) and the strong anionic detergent sodium dodecyl sulfate. the hydrophobic behavior of the glycoprotein, coupled to the high content of hydrophilic carbohydra ... | 1983 | 6323497 |
| structural organization and expression of human dna sequences related to the transforming gene of avian myeloblastosis virus. | bacteriophage libraries of human dna were screened for sequences homologous to the transforming gene (v-myb) of avian myeloblastosis virus. the three overlapping clones isolated were shown to contain a total of 1.0 kilobase pair (kbp) of sequence related to v-myb distributed over 6.2 kbp. restriction enzyme mapping and heteroduplex analysis revealed the presence of five myb-related domains interrupted by four stretches of non-homology. to study the extent of human dna coding sequences that const ... | 1983 | 6324165 |
| avian acute leukemia viruses. | 1983 | 6303707 | |
| 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 ... | 1983 | 6304685 |
| 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 ... | 1983 | 6305504 |
| the transforming gene of avian myeloblastosis virus (amv): nucleotide sequence analysis and identification of its translational product. | the genome of the avian myeloblastosis virus (amv) has undergone a sequence substitution in which a portion of the region normally coding for the env protein has been replaced by cellular sequences. we have determined the complete nucleotide sequence of this region. examination of the amv oncogenic sequence revealed an open reading frame starting with the initiation codon atg and terminating with the triplet tag within the acquired cellular sequences and terminating with the triplet tag at a poi ... | 1983 | 6305788 |
| high-level expression in escherichia coli of the carboxy-terminal sequences of the avian myelocytomatosis virus (mc29) v-myc protein. | a plasmid, pjl6, was constructed that contains a unique clai site twelve codons beyond the bacteriophage lambda cii gene initiation codon. this site allowed us to fuse the carboxy-terminal sequences of the avian myelocytomatosis virus (mc29) v-myc gene to the amino-terminal portion of the cii gene. transcription of the hybrid gene is controlled from the phage lambda pl promoter. when this promoter is derepressed, escherichia coli cells harboring the chimeric plasmid produce a level of cii-myc fu ... | 1983 | 6311677 |
| inhibition of retrovirus rna-dependent dna polymerase by novobiocin and nalidixic acid. | inhibitors of bacterial dna gyrase and eukaryotic dna topoisomerase (novobiocin and nalidixic acid) were investigated with respect to their effect on the activity of rna-dependent dna polymerases from murine and avian retroviruses. purified rna-dependent dna polymerase from akr virus was inhibited more than 90% by 0.3 mg/ml and almost completely by 1 mg/ml of the drugs when poly(a) x oligo(dt)12-18 was used as a template-primer. in contrast to the enzyme from akr virus, purified enzyme from avia ... | 1983 | 6311959 |
| characteristics and regulation of interaction of avian retrovirus pp12 protein with viral rna. | we investigated the interaction of the avian retrovirus pp12 protein with viral rna to assess its possible role in virion assembly. using chemical modification techniques, we found that reagents specific for lysine or arginine residues inactivated the rna-binding capacity of the protein. the binding of pp12 to 60s viral rna was also strongly affected by ph (pkapp of 5.5); the affinity for viral rna decreased by as much as 40-fold after protonation of one or more titratable groups on the protein. ... | 1983 | 6312093 |
| 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 ... | 1983 | 6316155 |
| 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 ... | 1983 | 6316156 |
| 5'-conformation of capped alfalfa mosaic virus ribonucleic acid 4 may reflect its independence of the cap structure or of cap-binding protein for efficient translation. | most eukaryotic mrnas are characterized by the presence of a 5'-terminal cap structure (m7gpppn), and removal of the cap or translation of capped mrnas in the presence of cap analogues (m7g) results in most cases in a significant decrease in the translational efficiency of the mrnas. one way of explaining the importance of the 5'-cap is that cap-binding proteins recognize the cap structure, destabilize the mrna secondary structure, and thus allow the 40s ribosomal subunit to bind to the mrna [so ... | 1983 | 6317016 |