| inhibition of the reverse transcriptase of bovine leukemia virus by antibody in sera from leukemic cattle and immunological characterization of the enzyme. | sera from some leukemic cattle contain an antibody that inhibits the reverse transcriptase activity of the bovine leukemia virus. the antibody is not directed against the synthetic template or the major internal and envelope viral antigens. the antibody failed to inhibit the dna polymerases of the murine leukemia virus, simian sarcoma-associated virus, avian myeloblastosis virus, or escherichia coli. conversely, the bovine leukemia virus enzyme was not inhibited by antibody against the reverse t ... | 1977 | 66983 |
| rapid purification of an rna tumor virus and proteins by high-performance steric exclusion chromatography on porous glass bead columns. | high-performance steric exclusion chromatography on a 1250-a pore size polyethylene glycol-treated glass bead column was used to purify avian myeloblastosis virus and hamster melanoma virus from plasma protein and tissue culture media. the purified hamster melanoma virus was still infectious and the avian myeloblastosis virus-associated rna-directed dna polymerase showed a 1100-fold purification of the virus from one column treatment. electron microscopy of the purified virus showed intact parti ... | 1977 | 67120 |
| new procedure for the direct analysis of in vitro reverse transcription of rous sarcoma virus rna. | based on the observation that in vitro transcription of rous sarcoma virus (rsv) rna by avian myeloblastosis virus dna polymerase renders the rna progressively more sensitive to escherichia coli rnase h digestion, a new procedure for the in situ analysis of this process has been developed. in vitro transcription products of 32p-labeled rsv rna are first treated with rnase h, the resistant fraction is then digested to completion with rnase t1, and the oligonucleotides are analyzed by a fingerprin ... | 1977 | 67218 |
| in vitro transcription of theavian oncornavirus genome by the rna-directed dna polymerase: analysis of dna transcripts synthesized in reconstructed enzymatic reactions. | we have analyzed the dna products synthesized in vitro in reconstructed reactions containing purified avian oncornavirus genome rna and rna-directed dna polymerase. the results of these studies indicate that: (i) the initial dna product synthesized on either 70s rna or reconstituted 35s rna-trnatrp template - primer complexes in the presence of low concentrations of deoxynucleoside triphosphates consists of several discrete size classes, none of which exceed 200 nucleotides in length; (ii) large ... | 1977 | 67224 |
| dna-polymerase inhibitors. rifamycin derivatives. | ten new derivatives of the antibiotic rifamycin with variable side chains at position 3 were synthesized. the inhibitory activity of these derivatives against dna-polymerases isolated from avian myeloblastosis virus, e. coli and calf thymus were studied at various conditions. 3-(2,4,6-trinitrophenylhydrazone-(methyl) rifamycin sv is a strong inhibitor for all the polymerases tested and belongs to the c class inhibitors of reverse transcriptase. 3-(monoallylhydrazone-(methyl) rifamycin sv possess ... | 1977 | 68462 |
| oligo(dg)12-18 aggregates result in non-homogeneity of oligo(dg)12-18.poly(c) type primer-template. | studies on the absorption spectra of equimolar solutions of oligo(dg)12-18 and poly(c), poly(cm) or poly(ce) showed that only 13%, 3% and 3% of base pairs, repectively, form complexes. upon centrifugation of oligo(dg)12-18 with a molar excess of poly(c) of poly(cm) in an analytical and a preparative centrifuge, it was found that only a part of oligodeoxynucleotide sediments with the polynucleotide, i.e. more rapidly than oligo(dg)12-18, poly(c) or poly(cm). products of binding of oligo(dg)12-18 ... | 1977 | 68464 |
| trnatrp (bovine) binding to the reverse transcriptase of avian myeloblastosis virus and function as a heterologous primer. | the primary structures for ttnatrp (bovine) and primer trnatrp (avian) show only minor differences in nucleotide sequence. the heterologous trnatrp (bovine) appears to have properties similar to the trnatrp (avian) in its ability to bind the alphabeta from of rna-dependent dna nucleotidyltransferase of avian myeloblastosis virus. a stable enzyme-trna complex has been isolated by gel filtration. in addition, trnatrp (bovine) can hydridize to the avian viral 35s rna and act as a primer for transcr ... | 1977 | 68471 |
| presence of dna polymerase in lymphosarcoma in northern pike (esox lucius). | northern poke lymphosarcoma dna polymerase was partially purified from particulate fractions banding at 1.15 to 1.16 g/ml from homogenates prepared from frozen necropsies of tumor-bearing pike. the enzyme behaves as a typical reverse transcriptase, in that it prefers ribotemplates to deoxytemplates. the isoelectric point (pl 5.5) is similar to that of avian myeloblastosis virus polymerase. the pike enzyme elutes from a phosphocellulose column at 0.22 m potassium phosphate, the same as avian myel ... | 1977 | 69492 |
| expression of endogenous retroviral genes in leukemic guinea pig cells. | the expression of guinea pig retrovirus (5-bromodeoxyuridine[budr]-induced gpv) was studied in guinea pig l(2)c leukemic lymphoblasts by use of molecular hybridization of viral complementary dna (cdna) to cellular rna. it was found that l(2)c leukemic lymphoblasts, leukemic spleen, and budr-induced virus-producing cells contain virus-specific rna: 0.05% (800 to 960 copies per cell), 0.02% (360 copies per cell), and 0.3% (5,120 copies per cell), respectively. adult normal liver and spleen, on the ... | 1977 | 69723 |
| [immunological approach to the study of the role of oncornavirus reverse transcriptase in neoplastic processes]. | | 1977 | 70126 |
| synthesis of a complementary dna to rat liver albumin mrna. | | 1977 | 70206 |
| interaction of tryptophan trna and avian myeloblastosis virus reverse transcriptase: further characterization of the binding reaction. | | 1977 | 70221 |
| extensive in vitro transcription of rous sarcoma virus rna by avian myeloblastosis virus dna polymerase and concurrent activation of the associated rnase h. | conditions are described that promote the efficient reverse transcription of most of rous sarcoma virus (rsv) rna sequences by avian myeloblastosis virus dna polymerase in vitro. a detailed analysis of the reverse transcription reaction was carried out using two procedures: in situ analysis of the rna sequences transcribed and dna-rna annealing studies. under optimal conditions, after 1 h of reaction, practically all rsv rna sequences were transcribed with a frequency varying from 30 to 90%. the ... | 1977 | 70539 |
| synthesis of full-length dna copies of avian myeloblastosis virus rna in high yields. | the synthesis of full-length complementary dna copies of avian myeloblastosis virus rna is described. the cdna is estimated by electrophoresis in agarose-methylmercury gels to have a molecular weight of 2.6 x 10(6), equivalent in size to that of the rna template. most (60-70%) of the reaction product is the full-length material and yields correspond to 60-70% of the input rna. | 1977 | 70785 |
| reverse transcription of phage rna and its fragment directed by synthetic heteropolymeric primers. | dna synthesis catalysed by rna-directed dna-polymerase (reverse transcriptase) was found to proceed on the rna template of an ms2 phage in the presence of heteropolymeric synthetic octa- and nonadeoxyribonucleotide primers complementary to the intercistronic region (coat protein binding site) and the region of the coat protein cistron, respectively. the product of synthesis consists of discrete dna fractions of different length, including transcripts longer than 1,000 nucleotides. the coat prote ... | 1977 | 71713 |
| detection of nanogram quantities of retraviral rna by assay with reverse transcriptase. | | 1977 | 71865 |
| reverse transcription of thyroglobulin 33-s mrna. | bovine thyroglobulin 33-s mrna has been used as a template for the synthesis of a complementary dna, using rna-directed dna polymerase from the avian myeloblastosis virus. the yield of the reaction was relatively poor and the size of the cdna did not exceed 10 s. nevertheless, a copy of high specific radioactivity (approximately 10(7) counts. min-1 microgram-1) could be obtained which hybridized specifically back to its template with an rot1/2 value about 5 times higher than that observed in hyb ... | 1977 | 71991 |
| in vitro transcription of the avian retrovirus genome by the alpha form of the viral rna-directed dna polymerase. | the nature of transcription of the avian retrovirus rna genome by the alpha form of the viral rna-directed dna polymerase has been investigated. transcription was most efficient when mn2+ was provided as the divalent metal ion. the patterns of dna transcription using 70s rna, 35s rna-trnatrp, or 35s rna-oligo(dt)12-18 template-primer complexes by the alpha dna polymerase were essentially identical to those obtained using the alphabeta form. the alpha dna polymerase appears to be deficient in the ... | 1977 | 72162 |
| [revertase in myeloblasts of chickens infected with avian myeloblastosis virus]. | revertase present in the myeloblasts of chickens infected with avian myeloblastosis virus failed to synthetise dna in vitro on the endogenous viral template. enzyme inhibitors were not blocking this synthesis. it was rather impaired by incompletness of viral rna in immature virus particles. | 1977 | 72475 |
| purification and further characterization of an rna-dependent dna polymerase from the allantoic fluid of leukosis-virus-free chicken eggs. | the purification of an rna-dependent dna polymerase from the allantoic fluid of uninfected, embryonated chicken eggs is described in detail. comparison to the polymerase of avian myeloblastosis virus shows that the two enzymes are different with respect to ion concentrations for optimal reaction, response to increasing concentrations of substrate, thermal stability and protection from thermal inactivation by viral rna. it is concluded that the enzymes compared to each other are different protein ... | 1977 | 72662 |
| synthesis by avian-myeloblastosis-virus rna-dependent dna polymerase of discrete reverse transcripts of bacteriophage rna polyadenylated in vitro. | | 1977 | 72663 |
| the effect of magnesium and manganese ions on the structure and template activity for reverse transcriptase of polyribocytidylate and its 2'-0-methyl derivative. | the secondary structure of the hydrogen bonded hybrids polycytidylate-oligodeoxguanylate (poly(rc)-(dg)12-18 and poly (2'-ome) cytidylate-oligodeoxyguanylate (poly (rcm)-(dg)12-18 was studied at several magnesium and manganese ion concentrations. these hybrids are effective template-primer complexes for the synthesis of poly(dg) by avian myeloblastosis virus (amv) dna polymerase under disparate ionic conditions. circular dichroism spectra and thermal melting data were obtained as a function of i ... | 1977 | 73165 |
| reverse transcriptase of foamy virus. purification of the enzymes and immunological identification. | reverse transcriptase from foamy virus, strain h4188 was estimated and purified. the enzyme has the following characteristics: 1. the reaction utilized preferentially oligo (dt) poly (ra) as a primer-template; however, the synthetic primer-template oligo (dt) poly (da) could also be used to some extent. 2. the reaction utilized oligo (dg) poly (rc) as a primer-template with very low efficiency. 3. the crude virus preparation had a detectable endogenous reaction using the four deoxyribonucleotide ... | 1977 | 74244 |
| effects of 5-tungsto-2-antimoniate in oncogenic dna and rna virus-cell systems. | | 1977 | 74337 |
| immunological characterization of the rna-dependent dna polymerase from reticuloendotheliosis virus. | | 1977 | 74790 |
| radioimmunoassay for the envelope glycoprotein of subgroup e avian leukosis-sarcoma viruses. | | 1978 | 74895 |
| chromatography of ovalbumin messenger ribonucleic acid on complementary deoxyribonucleic acid-cellulose. | dna complementary to ovalbumin mrna and covalently bound to cellulose (cdna-cellulose) was synthesized using avian myeloblastosis virus rna-directed dna polymerase. high concentrations of actinomycin d (200 migrogram/ml) were required to produce 97% inhibition of double-stranded dna synthesis, but mrna transcription was only slightly inhibited (14%). the conditions used for binding of mrna to cdna-cellulose permitted complete hybridization of ovalbumin mrna in 10 min while stable poly(a):(dt) hy ... | 1978 | 75208 |
| reverse transcriptase of rna tumor viruses. v. in vitro proteolysis of reverse transcriptase from avian myeloblastosis virus and isolation of a polypeptide manifesting only rnase h activity. | purified avian myeloblastosis virus reverse transcriptase contains two subunits that are structurally related. the large subunit, beta (molecular weight, 95,000), was converted in vitro by chymotrypsin into a polypeptide of molecular weight 63,000. this polypeptide was indistinguishable from the small subunit, alpha (molecular weight, 65,000), in its chromatographic behavior on the phosphocellulose column and its tryptic peptide composition. during this proteolytic conversion, a polypeptide of m ... | 1978 | 75271 |
| inhibition of rous sarcoma viral rna translation by a specific oligodeoxyribonucleotide. | a tridecamer oligodeoxynucleotide, d(a-a-t-g-g-t-a-a-a-a-t-g-g), which is complementary to reiterated 3'- and 5'-terminal nucleotides of rous sarcoma virus 35s rna, is an efficient inhibitor of the translation of proteins specified by the viral rna in the wheat embryo cell-free system. the inhibition specificity for oncornavirus rna is greater than for rabbit reticulocyte mrna or brome mosaic virus rna. other oligodeoxynucleotides of similar size have little or no specific effect on the rna-dire ... | 1978 | 75546 |
| purification and characterization of particles containing rna-dependent dna polymerase, in the allantoic fluid of uninfected leukosis virus-free chicken eggs. | the allantoic fluid of embryonated chicken eggs regularly contains particle-associated rna-dependent dna polymerase, as shown by its reaction with homopolymeric and heteropolymeric rna and by the characterization of the products. the purification of the particles is described. the purified particles are different from the known avian rna tumor viruses in their protein composition and their sedimentation constant. they do not exhibit biological properties typical for rna tumour viruses, such as h ... | 1978 | 75744 |
| interaction of 4'-(9-acridinylamino)methanesulfon-m-anisidide with dna and inhibition of oncornavirus reverse transcriptase and cellular nucleic acid polymerases. | 4'-(9-acridinylamino)methanesulphon-m-anisidide (amsa) (nsc 141549), an acridine derivative with activity against a variety of laboratory tumors in vivo, is presently undergoing phase 1 clinical evaluation. the interaction of amsa with dna and its effects on nucleic acid-polymerizing enzymes were examined in an attempt to define the site of cytotoxicity of amsa. binding of amsa to dna, as demonstrated by equilibrium dialysis and spectrophotometric methods, appears to be similar to other aminoacr ... | 1978 | 76512 |
| enzymatic synthesis of dna complementary to mitochondrial mrna via reverse transcription. | the poly(a)-containing mitochondrial mrnas of rat liver were tested for their ability to serve as templates for the dna synthesis by means of reverse transcription in the presence of the oligo(dt) primer and the rna-directed dna-polymerase from avian myeloblastosis virus. the mt-mrna does not support the dna synthesis in the standard conditions sufficient for effective reverse transcription of rabbit globin mrna and of poly(a) in the presence of oligo(dt) primers. after a mild alkaline treatment ... | 1978 | 77007 |
| [rna tumor virus-like particles in hodgkin's disease and in non-hodgkin lymphomas]. | | 1977 | 77100 |
| beta-lapachone, an inhibitor of oncornavirus reverse transcriptase and eukaryotic dna polymerase-alpha. inhibitory effect, thiol dependence and specificity. | beta-lapachone is a naturally occuring compound that can be isolated from a number of tropical trees. it is shown to be a potent inhibitor of reverse transcriptase activity from both avian myeloblastosis virus and rauscher murine leukaemia virus. in addition, it affects eukaryotic dna-dependent dna polymerase-alpha activity: 50% inhibition is reached in 60-min incubation time by about 8 micron beta-lapachone. enzyme activity is inhibited irrespective of the purity of the enzyme used or of the am ... | 1978 | 77223 |
| multiple rnase h activities in mammalian type c retravirus lysates. | lysates of moloney murine sarcoma-leukemia virus [m-msv(mlv)], a virus complex grown in the rat cell line 78a-1, were found to contain three rnase h species separable by polycytidylic acid[poly(c)]-agarose chromatography. rnase h activity (rnase h i) associated with rna-directed dna polymerase eluted at 0.23 m kci from poly(c)-agarose. rnase h ii, which eluted from poly(c)-agarose at 0.12 m kci and was not associated with dna polymerase activity, was shown to be identical to an rnase h species ( ... | 1978 | 77333 |
| binding of trna to reverse transcriptase of rna tumor viruses. | the interaction of trna with the reverse transcriptase (rna-dependent dna polymerase) of mammalian rna viruses, such as moloney murine leukemia virus and simian sarcoma virus, has been studied. whereas the purified reverse transcriptase of mammalian viruses sedimented in glycerol gradients as a globular protein with a molecular weight of 70,000, after interaction with trna the enzyme cosedimented with a protein of 150,000 molecular weight. the twofold increase in molecular weight could be a resu ... | 1978 | 77907 |
| proteins of rous-associated virus 61, an avian retrovirus: common precursor for glycoproteins gp85 and gp35 and use of pactamycin to map translational order of proteins in the gag, pol, and env genes. | cells infected by rous-associated virus 61 (rav-61) contained a precursor-like protein, pr90, that was specifically precipitated by antiserum directed against envelope glycoproteins, gp85 and gp35. tryptic peptide mapping showed that pr90 contained tryptic sequences of both gp85 and gp35. pactamycin mapping experiments indicated that the two glycoproteins are translated from the env-mrna in the order (5') gp85--gp35. the pactamycin mapping experiments also indicated a translational order of p10- ... | 1978 | 77910 |
| unwinding-like activity associated with avian retrovirus rna-directed dna polymerase. | the avian retrovirus rna-directed dna polymerase contains an activity that is capable of removing hydrogen bonds from duplex nucleic acid molecules. this "unwinding-like" activity appears to be specific in its action, affecting rna.dna and dna.dna duplex molecules but not rna.rna duplexes. studies with defined rna.dna hybrid molecules (e.g., rous sarcoma virus rna and complementary dnas representing specific regions of the rous sarcoma virus genome) and dna.dna duplexes indicate that, although t ... | 1978 | 77911 |
| normal chicken cells (chf-) express a surface antigen which cross-reacts with determinants of the major envelope glycoprotein (gp85) of avian myeloblastosis virus. | | 1978 | 78565 |
| the detection of glycoproteins immunologically related to rsv gp85 in uninfected avian cells and in sera from uninfected birds. | | 1978 | 78566 |
| avian oncornavirus associated n2-methylguanine transferase, location and origin. | | 1978 | 78705 |
| quantitative synthesis of full-length globin genes: dependence on template. | | 1978 | 78709 |
| template-specific requirements for dna synthesis by the mason-pfizer monkey virus dna polymerase: unique aspects. | the biochemical properties of dna polymerase purified from mason-pfizer monkey virus were studied, with respect to synthetic and natural template-primer utilization. thes studies revealed the following new information about the mason-pfizer monkey virus enzyme: (a) mason-pfizer monkey virus polymerase was found to prefer template: primer molar nucleotide ratios of 2.5-5: 1 for optimal rates of synthesis with poly(c) .(dg)12-18 as template-primer. (b) poly(a)-directed synthesis was stimulated b ... | 1978 | 78724 |
| synthesis of sindbis virus complementary dna by avian myeloblastosis virus rna-directed dna polymerase. | sindbis virus 42 s rna was efficiently transcribed into complementary dna (cdna) by avian myeloblastosis virus alphabeta dna polymerase using oligo- (dt) or single-stranded calf thymus dna as primers. both of the sindbis virus cdna products were able to protect 60% of 125i-labeled sindbis virus rna, at near equal weight ratios, from rnaase a and t1 digestion. using hybridization kinetics, the crt 1/2 value for hybridization of the calf thymus-primed cdna product with excess sindbis rna was deter ... | 1978 | 78725 |
| decreased levels of collagen mrna in rous sarcoma virus-transformed chick embryo fibroblasts. | we have found that double-stranded cdna synthesized in extended reactions by avian myeloblastosis virus reverse transcriptase is suitable substrate for a variety of restriction endonucleases. experiments in which rabbit reticulocyte mrna was reverse-transcribed and restricted to generate beta-globin-specifihe nucleotide sequence of beta-globin mrna. this method has been applied to study collagen mrna synthesis in normal and rous sarcoma virus (rsv)-transformed chick embryo fibroblasts. character ... | 1978 | 78927 |
| reverse transcriptase: a monitor for perturbation effects of spin labels covalently bound to nucleic acids. | the sensitive biological assay for reverse transcriptase was used to monitor potential perturbation effects of spin labels covalently bound to various nucleic acids or nucleic acid analogs to the extent of about one label per 100 residues. the inhibitory properties of the spin labeled and unlabeled biopolymers were compared for evaluating possible interference of the reporter group in protein-nucleic acid interaction studies. the amount of inhibitor required for 50% inhibition (ed50) was determi ... | 1978 | 79171 |
| discrimination of dna polymerase and rnase h activities in reverse transcriptase of avian myeloblastosis virus. | the active sites in reverse transcriptase of avian myeloblastosis virus have been selectively modified by various chemical reagents. the dna polymerase activity is very sensitive to hydrophobic sulfhydryl reagents such as 5,5'-dithiobis(2-nitrobenzoic acid) and p-hydroxymercuribenzoate but resistant to sulfhydryl reagents with hydrophilic properties. the rnase h activity, on the other hand, is resistant to both hydrophobic and hydrophilic sulfhydryl reagents, indicating the absence of cysteinyl ... | 1978 | 79419 |
| e. coli trnas as inhibitors of viral reverse transcription in vitro. | reverse transcription of 70s amv rna by amv reverse transcriptase has been studied in the presence of e. coli trnas. we have shown that inhibition of dna synthesis occurs and that the trnas bind to the enzyme and not to the 70s rna. the results have implications for the control of reverse transcription in vivo. | 1975 | 79997 |
| particles from mouse melanoma b16 containing reverse transcriptase and 70s rna related to human melanoma cytoplasmic rna. | the mouse melanoma b16 contains particles encapsulating high molecular weight rna of 60--70s size associated with a reverse transcriptase. the [3h]dna synthesized by these particles possesses homology with rna isolated from a hamster melanoma and from three human malignant melanomas. | 1978 | 80158 |
| inhibition of reverse transcription of 70s and 35s avian myeloblastosis rnas by nonprimer trna's. | we studied the kinetics of the reverse transcription of 70s and 35s rna of avian myeloblastosis virus in the presence and absence of various trna's. all trna's inhibited synthesis. trna's from escherichia coli and yeast exhibited a noncompetitive type of inhibition, i.e., they bound reversibly and randomly and did not alter the affinity of the viral rna for the polymerase. nonprimer trna's obtained from 70s rna molecules produced a complex pattern of inhibition. the results show that the nonprim ... | 1978 | 80459 |
| aphidicolin: a specific inhibitor of dna polymerases in the cytosol of rat liver. | | 1978 | 81050 |
| reverse transcriptase-associated rnase h activity. ii. inhibition by natural and synthetic rna. | the rnase h activity associated with purified avian myeloblastosis virus and rauscher murine leukemia virus dna polymerases is inhibited by homopolymeric rna molecules, although the efficiency of inhibition by each homopolymer appears enzyme specific. formation of duplex rna molecules abolished the inhibitory activity. in contrast to these results, dna polymerase-independent rnase h activities, such as the rnase h-ii from rauscher murine leukemia virus and calf thymus rnase h, were unaffected by ... | 1978 | 81313 |
| virus-coded origin of a 32,000-dalton protein from avian retrovirus cores: structural relatedness of p32 and the beta polypeptide of the avian retrovirus dna polymerase. | a 32,000-dalton protein (p32) located in avian retrovirus cores was immunoprecipitated from [35s]methionine-labeled avian myeloblastosis virus (amv) propagated in cultured chicken embryo fibroblast cells by an antiserum preparation (sarc iii) derived from tumor-bearing hamsters injected with cloned and passaged cells from an avian sarcoma virus-induced primary hamster tumor. since sarc iii serum apparently contained antibodies only to virus-coded proteins and not to chicken cellular proteins, th ... | 1978 | 81316 |
| isolation and characterization of a virus-specific ribonucleoprotein complex from reticuloendotheliosis virus-transformed chicken bone marrow cells. | chicken bone marrow cells transformed by reticuloendotheliosis virus (rev) produce in the cytoplasm a ribonucleoprotein (rnp) complex which has a sedimentation value of approximately 80 to 100s and a density of 1.23 g/cm3. this rnp complex is not derived from the mature virion. an endogenous rna-directed dna polymerase activity is associated with the rnp complex. the enzyme activity was completely neutralized by anti-rev dna polymerase antibody but not by anti-avian myeloblastosis virus dna poly ... | 1978 | 81319 |
| comparison of the rna-dependent dna polymerase of an endogenous avian leukosis virus to the polymerase of an exogenous avian leukosis virus. | rna-dependent dna polymerases from rous-associated virus-o and avian myeloblastosis virus were partially purified by affinity chromatography and compared to each other. the enzymes are indistinguishable in the immunoglobulin inhibition test and by several enzymological criteria, such as optimum curves for the concentrations of mg2+, k+, h+; monophasic lineweaver-burk plot for dttp and biphasic lineweaver-burk plot for dgtp. in thermal inactivation studies a small difference can be observed, sugg ... | 1978 | 81774 |
| isolation and characterization of the envelope glycoprotein of an avian osteopetrosis virus: effect of host cell on antigenic reactivity. | | 1978 | 82295 |
| effects of benzo(a)pyrene adducts of dna synthesis in vitro. | two diol epoxides of benzo(a)pyrene (bp), and benzo(a)pyrene 4,5-oxide, have been used to make adducts in the homopolymers polyribocytidylic acid, (rc); polyriboadenylic acid (ra), polydeoxycytidylic acid (dc) and polydeoxyadenylic acid (da). with appropriate oligomers as primers these modified and unmodified polynucleotides were used as templates for dna synthesis with avian myeloblastosis virus dna polymerase (amv) or e. coli pol i dna polymerase. we have found that: (1) the size of the dna pr ... | 1978 | 82490 |
| [immunofluorescent demonstration of rna-dependent dna polymerase (reverse transcriptase) in xc cells]. | | 1978 | 82504 |
| recognition sequence of restriction endonuclease kpni from klebsiella pneumoniae. | we have determined the recognition sequence of the restriction endonuclease kpni, previously isolated from klebsiella pneumoniae. the enzyme cleaves the twofold rotationally symmetric sequence (see book for formula) at the positions indicated by the arrows, producing 3' protruding cohesive ends, four nucleotides in length. the specific cleavage site was unambiguously deduced using both 3' and 5' end analyses of kpni generated restriction fragments of simian-virus 40 (sv40) dna (1 site), adenovir ... | 1978 | 82935 |
| reverse transcription of turnip yellow mosaic virus rna primed with calf-thymus dna hydrolysate: characterization of the purified cdna product. | complementary dna was transcribed from turnip yellow mosaic virus rna, using the method of taylor et al. (1). the purified cdna thus obtained sedimented between 2 and 4 s and was a mostly uniform transcript of template rna. it hybridized with a sharp transition to homologous tymv-rna (crt 1/2 = 2.7 x 10(-2)), but showed a low level of hybridization (less than 5%) to the rnas of two other tymoviruses, namely andean potato latent virus and eggplant mosaic virus. | 1978 | 82938 |
| biochemical and immunological characterization of a reverse transcriptase from human melanoma tissue. | an rna-direct dna polymerase was purified from human melanoma tissue by successive column chromatography on deae-cellulose (de-23 and de-52) and phosphocellulose. the purified reverse transcriptase has a mol. wt. of 68,000, a ph optimum of 8.0, a mn2+ optimum of 0.6 mm, and a kcl optimum of 60 mm. the purified enzyme transcribes (ra)n - (dt)12, (rc)n - (dg)18, (ome-rc)n - (dg)18 and a 70s rna from rauscher leukemia virus (rlv), but failed to transcribe (da)n - (dt)12. this enzyme has no terminal ... | 1978 | 83188 |
| effects of testosterone on sequence complexity of polyadenylated rna from rat seminal vesicle. | | 1978 | 83232 |
| endonuclease activity of purified rna-directed dna polymerase from avian myeloblastosis virus. | highly purified preparations of rna-directed dna polymerase from avian myeloblastosis virus (amv) contain a mn2+-activated endonuclease activity capable of nicking supercoiled dna. this endonuclease activity co-sediments in glycerol gradients with the alphabeta form of amv dna polymerase, and co-chromatographs with dna polymerase activity on deae-cellulose, phosphocellulose, and heparin-sepharose. it is also present in amv alphabeta-dna polymerase purified by electrophoresis through nondenaturin ... | 1979 | 83998 |
| efficient reverse transcription of cowpea mosaic virus rnas. | conditions are described which give an efficient synthesis of dna copies of cowpea mosaic virus (cpmv) rnas, using avian myeloblastosis reverse transcriptase and oligo (dt) primers. maximum incorporation of damp into cdna is attained with 0.4 to 0.8 mm of each deoxynucleoside triphosphate, 12 mm mg++ and 60 mm k+ ion concentrations. high enzyme concentrations (up to 100 units/ml) were used. under these conditions over 1000 pmoles of damp were incorporated per reaction. the cdna:rna molar ratio ... | 1978 | 85293 |
| alpha-fetoprotein and albumin genes of rats: no evidence for amplification-deletion or rearrangement in rat liver carcinogenesis. | full-length radiolabeled albumin and alpha-fetoprotein (afp) cdnas were synthesized from pure albumin and amp mrna preparations by using avian myeloblastosis virus reverse transcriptase (rna-dependent dna polymerase). the cdnas have been used to quantitate the number of albumin and afp genes in different rat tissues by two independent methods, both of which yielded similar results. first, the kinetics of the association of these cdnas with nuclear dna from rat liver, rat kidney, and morris hepat ... | 1979 | 85303 |
| demonstration of an unusual dna polymerase activity associated with the l cell virion. | purified preparations of l cell virions (lcv) were found to possess an associated dna polymerase activity. this enzyme was active with poly(c).oligo(dg) and poly(cm).oligo(dg) and was able to transcribe poly(a).oligo(dt). endogenous dna synthesis was also demonstrable in disrupted virion preparations but this reaction was enhanced, rather than inhibited, by rnase pre-treatment. the effects of variations in a number of the assay parameters on these activities were examined in an attempt to determ ... | 1979 | 85690 |
| reverse transcriptase from avian myeloblastosis virus. | from lots of 20 to 30 g of avian myeloblastosis virus rna-dependent dna polymerase was obtained in preparations of purity greater than 95% by using a two-step column chromatographic procedure employing deae (de 52) and carboxymethylcellulose (cm 52.). yields of rna-dependent dna polymerase varied from approximately 20,000 to 35,000 u/g of virus. specific activity of the enzyme was about 35,000 to 60,000 u/mg of protein. free of detectable rnase activity, the product exhibited a molecular weight ... | 1979 | 85721 |
| analysis of the genetic complexity and abundance classes of messenger rna in human liver and leukemic cells. | in an effort to determine the number of genes expressed as messenger rna in disparate human tissues we have analyzed the genetic complexity of the polyribosome-associated poly(a)-containing rna population obtained from liver and lymphoblastic leukemic cells. this was accomplished by measuring the kinetics of hybridization of mrna to a complementary dna probe synthesized by avian myeloblastosis virus reverse transcriptase in vitro. the results obtained from such an analysis revealed the presence ... | 1979 | 86365 |
| double-stranded protamine cdna: synthesis and characterization. | double-stranded protamine complementary dna (cdna) was synthesized from a protamine mrna template via the single-stranded cdna intermediate using avian myeloblastosis virus reverse transcriptase. synthesis at 37 and 46 degrees c resulted in similar overall yields (greater than or equal to 18%), although the initial rate of synthesis was higher at 46 degrees c than at 37 degrees c. the dna of the second strand of the double-stranded cdna product was 84% resistant to prolonged digestion with exces ... | 1979 | 86381 |
| the isolation of avian viral rna and polypeptides. | from the same batch of virus, the four major avian viral structural proteins p27, p19, p15, and p12, the reverse transcriptase, the envelope glycoprotein gp85, and the high molecular weight 70 s rna have been recovered. all proteins, except for gp85, have been purified by use of column chromatography procedures to apparent homogeneity as judged by sodium dodecyl sulfate-polyacrylamide gels and isoelectric focusing. a new isolation procedure for p12 by affinity column chromatography takes advanta ... | 1979 | 86539 |
| reverse transcriptase-associated ribonuclease h does not require zinc for catalysis. | omicron-phenanthroline, a zinc chelating agent, is known to inhibit the dna polymerase activity of cellular dna-dependent and viral rna-dependent dna polymerases. we find that omicron-phenanthroline does not inhibit the reverse transcriptase-associated rnase h activity of retroviruses. kinetic studies, using dna template-primers as an inhibitor of rnase h, suggest that zinc does not play any role in template-primer binding by reverse transcriptase. these results also indicate a distinct binding ... | 1979 | 86544 |
| ["revertase" project: results of carrying out the scientific program]. | the article summarizes the data obtained within the scope of the "revertase" project organized in 1972 under the guidance of scientific councel on molecular biology. the scientific program included four main topics: synthesis of complementary dna via reverse transcription on the various rna templates and their use as tools in molecular biology, enzymatic synthesis of structural genes in double dna-polymerase system and their propagation by means of genetic engineering, enzymology of reverse tran ... | 1979 | 86943 |
| [reverse transcription of the rna of eukaryotes and viruses. conditions for obtaining a long product]. | the receiving of full-size dna-copies of rnas is necessary for molecular hybridisation experiments as well as for synthesis of recombinant bacterial plasmids with eucariotic dna sequences. some authors received such cdnas for different rnas with a help of variations in reaction conditions. in this article it is shown that such empirically chosen conditions mainly had an influence on a secondary structure of rna-templates and that only in such a case the synthesis of the dna-product with sizes co ... | 1979 | 86944 |
| apparent allosterism by avian myeloblastosis virus reverse transcriptase and e. coli dna polymerase i. | a recent report (1) presented evidence for allosterism in reverse transcription by mason-pfizer monkey virus reverse transcriptase and by e. coli dna polymerase i. our experiments also demonstrate these apparent cooperative effects when synthesis is catalyzed by either avian myeloblastosis virus dna polymerase, feline sarcoma virus dna polymerase, or e. coli dna polymerase i (large fragment). we show that the apparent cooperativity depends on the use of oligo(dt)12-18 as primer. however, if the ... | 1979 | 86985 |
| synthesis of long complementary dna in the endogenous reaction by equine infectious anemia virus. | in the endogenous reverse transcriptase reaction, equine infectious anemia virus is able to synthesize complementary dna (cdna) of 8,000 nucleotides in high yield. after 2 h in 50 mum dntp, about 2.8 mug of cdna per mg of protein is produced, almost 30% of which is long cdna. the system thus compares favorably with the other two well-characterized endogenous reaction systems, moloney murine leukemia virus and avian sarcoma virus. elongation rates of 100 to 150 nucleotides per min have been obser ... | 1979 | 87522 |
| inhibition of reverse transcriptase activity by benzophenanthridine alkaloids. | benzophenanthridine alkaloids, fagaronine 4, o-methylfagaronine 5,nitidine 1, allonitidine 3 and methoxydihydronitidine 2 have been shown to possess inhibitory activity against reverse transcriptase of rna tumor viruses. the enzyme inhibition (50%) by these alkaloids was found in the range of 6-60 microgram per milliliter of the reaction mixture when polynucleotide-oligodeoxynucleotide complexes were used as template primers. the results suggested that the benzophenanthridine alkaloids interacte ... | 1979 | 88001 |
| [immunologic aspects of preparation of antiserum to the reverse transcriptase from avian myeloblastosis virus]. | after immunization of rabbits the antiserum was prepared against purified reverse transcriptase (revertase) from avian myeloblastosis virus (amv). the antiserum demonstrated enzymeneutralizing antibody activity that was associated with ummunoglobulin g fraction but not with igm. the high antigenicity of amv revertase for rabbits was shown. the active antiserum was obtained after 4 immunizations of rabbit with approximately 20 microgram of the enzyme. non-specific revertase inhibitors were found ... | 1976 | 88006 |
| a new method for the size estimation of the rna genome segments of influenza virus. | previous estimates of the size of the rna genome segments of influenza virus have been unreliable because of a lack of suitable rna species as size markers. we have attempted to overcome this problem by utilising the ability of amv reverse transcriptase to synthesise full length dna copies of rna molecules in the presence of a suitable primer. by comparing such dna copies of the rna segments of the influenza virus genome with sequenced restriction fragments from the e. coli plasmid pbr322, we ha ... | 1979 | 88039 |
| primer trnatrp enhances the inhibition of avian myeloblastosis virus reverse transcriptase by pyridoxal-5'-phosphate. | | 1979 | 88226 |
| influence of various 2- and 2'-substituted polyadenylic acids on murine leukemia virus reverse transcriptase. | several newly synthesized polyadenylic acid [(a)n] analogues, including poly(2-methyladenylic acid) [(m2a)n], poly(2-ethyladenylic acid) [(e2a)n], poly(2-isopropyladenylic acid) [(i-pro2a)n], poly(2-methylthioadenylic acid) [(ms2a)n], poly(2-ethylthioadenylic acid) [(e2a)n], poly(2'-fluoro-2'-deoxyadenylic acid) [(dafl)n] and poly(2'-azido-2'-deoxyadenylic acid) [(daz)n] have been evaluated for their effects on the rna-directed dna polymerase (reverse transcriptase) activity of moloney murine le ... | 1979 | 88259 |
| kinetic complexity of nuclear poly(a)-containing rna in normal and regenerating rat liver. | poly(a)-containing rna isolated from liver nuclei of untreated rats and 3 h or 12 h after partial hepatectomy or sham operation was hybridized to the complementary dnas (cdnas). in the homologous reactions two major components could be seen. when compared to normal liver, the complexity of the least abundant class was lower in nuclei from livers 3 h after partial hepatectomy and was higher in those isolated 12 h after operation. the heterologous reactions revealed an increase of some abundant p ... | 1979 | 88367 |
| [mrna of mouse plasmacytoma. reverse transcription and translation in cell-free systems]. | total poly(a)-mrna from polyribosomes of mopc 21 mouse myeloma were investigated. poly(a)-mrna was released by two successive chromatography on oligo (dt)-cellulose. a 14s fraction of total poly(a)-mrna was obtained and partially purified by sucrose gradient centrifigation followed by acrylamide gel electrophoresis. as estimated from the electrophoretic analysis, the 14s mrna has three components, one of which appears to be 18s rrna and two others--mrnas with molecular weight of 5.2.10(5) and 3. ... | 1979 | 88667 |
| homology in the 3'-terminal region of rnas from rna coliphages. | | 1979 | 88800 |
| model rna-directed dna synthesis by avian myeloblastosis virus dna polymerase and its associated rnase h. | a model rna template-primer system is described for the study of rna-directed double-stranded dna synthesis by purified avian myeloblastosis virus dna polymerase and its associated rnase h. in the presence of complementary rna primer, oligo(ri), and the deoxyribonucleoside triphosphates dgtp, dttp, and datp, 3'-(rc)30-40-poly(ra) directs the sequential synthesis of poly(dt) and poly(da) from a specific site at the 3' end of the rna template. with this model rna template-primer, optimal condition ... | 1979 | 88956 |
| enzymic polyadenylation of 5s ribosomal ribonucleic acid and synthesis of a complementary deoxyribonucleic acid. | the 5s ribosomal rna has been isolated, pure and intact, from rat liver (5 mg of 5s rna from 150g of liver). the 5s rna serves as a primer for calf thymus poly(a) polymerase with 20% of the efficiency of (ap)3a. bacterial 5s rna and transfer rna also serve as primers; rat liver 18s and 28s ribosomal rnas support poly(a) synthesis poorly. neither the 5s rna primer nor the appended poly(a) tract is nicked or degraded by poly(a) polymerase, and initiation of poly(a) tracts on 5s rna primers continu ... | 1979 | 88957 |
| immunochemical studies of beef pancreas tryptophanyl-trna synthetase and its fragments. determination of the number of antigenic determinants and a comparison with tryptophanyl- trna synthetases from other sources and with reverse transcriptase from avian myeloblastosis virus. | the immunoglobulin g (igg) fraction of the antiserum from rabbits immunized with homogeneous beef pancreas tryptophanyl-trna synthetase inhibits the enzyme activity in the reactions of both trnatrp aminoacylation and tryptophan activation. fab fragments of igg act in a similar way. common antigenic determinants have been detected in tryptophanyl-trna synthetases from beef, pig, chicken and rat livers using pure antibodies against beef pancreas tryptophanyl-trna synthetase. this observation indic ... | 1979 | 89031 |
| methylmercury hydroxide enhancement of translation and transcription of ovalbumin and conalbumin mrna's. | translation of total mrna in heterologous protein-synthesizing systems is often employed as an indirect means of assessing relative mrna concentrations. however, it is well known that the efficiency of translation of specific mrnas differs. one such example is the poor translational efficiency of conalbumin mrna relative to ovalbumin mrna. in this report we have studied the translation of conalbumin and ovalbumin mrnas in crude mrna preparations and with highly purified mrna preparations. we fin ... | 1979 | 89113 |
| interactions of retroviruses with chemical carcinogen. i. noncovalent binding of unactivated polycyclic aromatic hydrocarbons. | | 1979 | 89755 |
| studies on the interaction of trna and avian myeloblastosis dna polymerase. | | 1979 | 89926 |
| biochemical characterization of the type c retrovirus associated with lymphoproliferative disease of turkeys. | turkeys inoculated with spleen extracts from lymphoproliferative disease (lpd)-affected birds developed viremia, followed by typical lpd lesions. electron microscopy and biochemical characterization established that the virus present in the blood of infected turkeys is a type c retrovirus. the viral particles possess a buoyant density of 1.17 g/ml in sucrose gradients; they contain high-molecular-weight rna and an rna-instructed dna polymerase with efficient exogenous and endogenous activity. th ... | 1979 | 90160 |
| in vitro cleavage of avian retrovirus gag proteins by viral protease p15. | | 1979 | 90424 |
| characterization of an rna-directed dna-polymerase from a cell line derived from a radiation-induced lymphoma in mice. | an rna-directed dna polymerase was purified from a cell line derived from a radiation-induced lymphoma in nih swiss mice which produced non-infectious type c virus particles. the enzyme was isolated from a high speed particulate fraction which bands at a density of 1.16--1.19 g/ml in a sucrose gradient, and purified by successive chromatography on deae-cellulose, phosphocellulose and hydroxyapatite. the purified dna polymerase has a molecular weight of 68 000, a ph optimum of 7.5, a kcl optimum ... | 1979 | 90522 |
| reverse transcriptase mediated binding of primer trna to the viral genome. | a complex between trnatrp (beef) and 35 s rna from avian myeloblastosis virus is obtained when the mixture is preincubated in the presence of reverse transcriptase at 35 degrees c. the trna-rna complex is active in initiating dna synthesis catalyzed by reverse transcriptase. the interaction of trna with reverse transcriptase involves the partial unwinding of the acceptor stem of trna, as evidenced by nuclease digestion with rnaase t1 and micrococcal nuclease. when trna2glu (coli), having a high ... | 1979 | 91158 |
| sequence homology adjacent to the 3' terminal poly(a) of cowpea mosaic virus rnas. | we have determined the sequence of 80 nucleotides adjacent to 3' poly(a) of both (middle and bottom component) cowpea mosaic virus rnas, using dideoxynucleotide termination of reverse transcription. sequence conservation is indicated, there being about 80% homology between the first 65 bases of each rna. although both rnas are polyadenylated, there is no aauaaa sequence as associated with most known polyadenylated mrnas of eukaryotes and viruses. however both rnas are u and a-rich in this region ... | 1979 | 91160 |
| reverse transcriptase pauses at n2-methylguanine during in vitro transcription of escherichia coli 16s ribosomal rna. | a restriction fragment strand complementary to a sequence near the 3' end of escherichia coli 16s rrna has been used to prime reverse transcriptase (avian myeloblastosis virus rna-directed dna nucleotidyltransferase; deoxynucleosidetriphosphate:dna deoxynucleotidyltransferase, ec 2.7.7.7). in addition to transcripts that were extended to the 5' end of the rna, two major transcription intermediates were observed. these discrete-sized cdna intermediates are the result of a kinetic barrier imposed ... | 1979 | 91169 |
| preparation of complementary dna to 5 s ribosomal rna from xenopus laevis. | | 1979 | 91536 |
| inhibition of reverse transcriptase activity by benzophenanthridine alkaloids. | benzophenanthridine alkaloids, fagaronine 4, o-methylfagaronine 5, nitidine 1, allonitidine 3 and methoxydihydronitidine 2 have been shown to posses inhibitory activity against reverse transcriptase of rna tumor viruses. the enzyme inhibition (50%) by these alkaloids was found in the range of 6-60 microgram per milliliter of the reaction mixture when polynucleotide-oligodeoxynucleotide complexes were used as template primers. the results suggested that the benzophenanthridine alkaloids interacte ... | 1979 | 91665 |
| [enzymatic synthesis and characterization of dna complementary to ceruloplasmin mrna from rat liver]. | poly(a) containing rat liver 21s rna homogeneous in polyacrylamide gel electrophoresis under denaturing conditions and stimulating the synthesis of ceruloplasmin in a cell-free proteinsynthesizing system, was used as a template for reverse transcription in the presence of t10 primer and highly purified reverse transcriptase from avian myeloblastosis virus. the cdna made this way was characterized by means of hybridization kinetics with mrna, by melting of the hybrids formed and by chain length m ... | 1979 | 91944 |
| new procedure for the production of influenza virus-specific double-stranded dna's. | a novel technique is described for the production of pure, full-length influenza virus ds dna's corresponding to each segment of the influenza virus genome, and suitable for molecular cloning and restriction endonuclease mapping. the method involves the synthesis of dna complementary to both virion (negative strand) and messenger (positive strand) rna, gel purification and annealing. by avoiding the use of si nuclease, which often removes the terminal regions of dna duplexes, the method allows t ... | 1979 | 92012 |
| problems with particle-associated dna polymerase assays in the diagnosis of plasma-suspended viruses. | the in vitro reaction results of virus-associated dna polymerases for the demonstration of plasma-suspended particles of avian leukemia virus (amv) and of hepatitis type b virus (hbv) were compared. amv particles could be identified by the transcription of the templates poly mc(dg)12-18, poly rat10, and poly d(at) using standardized reaction mixtures. with comparable test conditions, no dna polymerase activity was found in human plasma containing hbv. these findings and the results of a systemat ... | 1979 | 92114 |