| [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 |
| 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 |
| 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 |
| 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 |
| 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 |
| human serum lyses rna tumour viruses. | | 1975 | 170540 |
| relationship of the first step in protein synthesis to ppgpp: formation of a(5')ppp(5')gpp. | in the presence of purified escherichia coli lysyl-trna synthetase [l-lysine:trnalys ligase (amp-forming) ec 6.1.1.6], l-lysine, and atp, addition of the nucleotide ppgpp results in formation of a unique product-a(5')ppp(5') gpp. the same compound is also formed very rapidly in a cell-free protein-synthesizing system when ppgpp is added. the possible significance of this reaction in the rapid turnover of ppgpp and as a more general mechanism by which an amp residue is activated and introduced on ... | 1975 | 170611 |
| 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 |
| 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 |
| 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 |
| susceptibility and resistance of chicken macrophages to avian rna tumor viruses. | | 1975 | 171840 |
| focus assay and defectiveness of avian myeloblastosis virus. | | 1975 | 171844 |
| leukemic transformation with avian myeloblastosis virus: present status. | | 1975 | 172289 |
| 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 |
| utilization of mismatched initiator termini by avian myeloblastosis virus dna polymerase. | dna synthesis by avian myeloblastosis virus was studied using poly(c) as template and modified oligo(dg) as primer. the addition of one noncomplementary base to the 3'-end of the primer has no important effect on synthesis. the mispaired base is incorporated into the product and the apparent km (for primer) and the v of the reaction remain unchanged. this confirms the absence of a 3' leads to 5'-exodeoxynuclease activity using a template that is transcribed faithfully rather than one that can un ... | 1979 | 92999 |
| trna's associated with the 70s rna of avian myeloblastosis virus. | the distribtuion of various amino acid trna's in the 4s rna components of avian myeloblastosis virus (amv) and in 4s rna prepared from chicken cmbryo cells, chicken myeloblasts, and chicken livers was determined. this was done by aminoacylating the 4s rna samples with a mixture of 17 radioactive amino acids and subsequently identifying the trna-accepted amino acids on an amino acid analyzer after deacylation. in embryo cells, myeloblasts, and liver, trna's accepting all 1m amino acids were demon ... | 1975 | 172660 |
| manganese as a mutagenic agent during in vitro dna synthesis. | | 1975 | 173332 |
| [separation of cellular and viral dna polymerase from oncornavirus infected chicken cells]. | rna-directed dna polymerase was isolated from the liver, spleen, and myeloblasts of chickens that had been infected with virus of avian myeloblastosis. the enzyme was chromatographically purified from the myeloblasts and brought to about 1,000-fold concentration. the method consisted in cell fractionation, lysis of the microsomal fraction, chromatography on sephadex g-200 and phosphocellulose, as well as ultracentrifugation in the glycerol gradient. the cellular dna polymerases alpha and beta we ... | 1979 | 93956 |
| comparison of an avian osteopetrosis virus with an avian lymphomatosis virus by rna-dna hybridization. | myeloblastosis-associated virus (mav)-2(0), a virus which was derived from avian myeloblastosis virus and induced a high incidence of osteopetrosis, was compared with avian lymphomatosis virus 5938, a recent field isolate which induced a high incidence of lymphomatosis. the following information was obtained. (i) mav-2(0) induced osteopetrosis, nephroblastoma, and a very low incidence of hepatocellular carcinoma. no difference was seen in the oncogenic spectrum of end point and plaque-purified m ... | 1975 | 173880 |
| translation of oncogenic virus rna in xenopus laevis oocytes. | | 1976 | 175294 |
| an approach to c-type virus immunoprevention of spontaneously occurring tumors in laboratory mice. | a review of our current progress in c-type virus vaccine research is presented. this includes the findings of c-type virus or its antigen expressions in every naturally occurring tumor of two strains of "low-incidence" laboratory mice, the balb/ccr mouse and the nih swiss mouse. vaccine preparation methods are described including the inactivation of c-type virus infectivity with optimal maintenance of the antigen titers of at least two of the polypeptides of the c-type virus, gp69/71 and p30. th ... | 1976 | 175922 |
| hepatitis b viral dna molecules have cohesive ends. | hepatitis b virus dna made fully double stranded by a virion dna polymerase reaction could be converted from circular to linear molecules by heating in 10 mm nacl at 77 degrees c or in 100 mm nacl at 90 degrees c for 15 min. heat-generated linear hepatitis b virus dna was reannealed to circular molecules by incubating in higher salt concentrations. the identity of the molecular forms was established by their electrophoretic mobility and appearance in electron micrographs. recircularization was b ... | 1979 | 94358 |
| release of particle associated rna dependent dna polymerases by primary chicken and quail embryo cells. | these results show that primary chick embryo cells in culture release a particle bound rna dependent dna polymerase into the culture fluid. the enzyme is also found in the allantoic fluid of embryonated chicken eggs. this phenomenon is not restricted to the chicken system because primary quail embryo cells which are not known to express the so far known endogenous viruses release a particle bound rna dependent dna polymerase as well. in both cases this enzymes may be part of an hitherto unknown ... | 1979 | 94582 |
| immunodiffusion study on group-specific antigen of mc-29 chicken hepatoma. | rabbit serum against crude mc-29 hepatoma extract does not contain anti-avian gs antibodies detectable by gel diffusion methods. rabbit serum containing antibodies against purified gs 1, gs 2, gs 3 and gs 4 antigens of avian myeloblastosis virus reveals gs 1 antigen in mc-29 hepatoma extract. | 1979 | 95333 |
| hydrodynamic diameters of rna tumor viruses. studies by laser beat frequency light scattering spectroscopy of avian myeloblastosis and rauscher murine leukemia viruses. | the diffusion constants of avian myeloblastosis virus (amv) and murine leukemia virus (mulv) (rauscher) suspensions in buffer and in 30% sucrose were determined by laser beat frequency light scattering spectroscopy at a series of temperatures ranging rom 5 to 25 degrees. by the use of the stokes-einstein equation, the following hydrodynamic diameters are calculated at 20 degrees: mulv, 154 plus or minus 3 nm in sucrose and 145 plus or minus 7 nm in buffer; amv, 144 plus or minus 3 nm in sucrose ... | 1975 | 162827 |
| affinity chromatography of viral dna polymerases on pyran-sepharose. | pyran covalently linked to cyanogen bromide-activated sepharose has been shown to be an effective affinity matrix for several viral dna polymerases. differential salt elution of viral compared with cellular polymerases, as well as substrate elution, suggests the affinity nature for the matrix. unlike some other affinity systems described, pyran-sepharose is totally resistant to nuclease digestion and is stable at 4 degrees for several months. dna polymerases isolated from several viruses by dete ... | 1975 | 165485 |
| inhibition of rna-dependent dna polymerase reaction by 6-(p-hydroxyphenylazo)-uracil: a result of drug induced dithiothreitol oxidation. | 6-(p-hydroxyphenylazo)-uracil (hpura) reduced by dithiothreitol inhibited amv or rlv virion associated exogenous rna-dependent dna polymerase reactions. however, the inhibition was variable from experiment to experiment and was not consistent with the base specificity of hpura seen for inhibition of gram positive dna-dependent dna polymerases. increasing the concentration of dithiothreitol reversed the inhibition. furthermore, at non-toxic concentrations, hpura did not influence the plating effi ... | 1975 | 166420 |
| growth stimulation of chicl embryo neuroretinal cells infected with rous sarcoma virus: relationship to viral replication and morphological transformation. | | 1976 | 179205 |
| on the fidelity of dna replication. characterization of polynucleotides with errors in base-pairing synthesized by avian myeloblastosis virus deoxyribonucleic acid polymerase. | polynucleotide templates were copied by avian myeloblastosis virus dna polymerase ("reverse transcriptase") and the frequency and distribution of errors were determined. the error rate with [r(pa)2500-d(pt)12-18] template-initiator under a variety of conditions was approximately 1/600, i.e. one incorrect dcmp incorporated for 600 correct dtmp polymerized. addition of the metal chelator o-phenanthroline to the reaction inhibited the incorporation of correct and incorrect nucleotides proportionate ... | 1975 | 166992 |
| functional possibilities for aminoacylation of viral rna in transcription and translation. | rna from at least ten viruses, representing more than four different group, is known to specifically bind in amino acid in a trna-like manner. the biological function of aminoacylation of rna from these viruses and of trna association with tumor viruses and bacteriophage, is discussed. hypothetical schemes are presented for a role for aminoacylation in viral translational and transcriptional mechanisms, and the current evidence relating to these models is presented. | 1976 | 179456 |
| two levels of genetic resistance to lymphoid leukosis. | two levels of genetic resistance to lymphoid leukosis are recognized: 1) cellular resistance to virus infection; and 2) resistance to tumor development in leukosis-virus-infected birds. resistance to infection is simply inherited but is very specific for the subgroup of virus. inheritance of resistance to tumor development is more complex but appears to be less subgroup-specific. a breeder may wish to select for resistance to infection of virus eradication is the goal. if his goal is the reducti ... | 1975 | 168849 |
| studies on characterization of the integration sites of avian rna tumor virus-specific dna. | a sequential hybridization procedure is described which allows the integration sites of viral-specific dna to be characterized according to their reassociation kinetics. in addition, this approach enables us to estimate the size of the integrated viral dna. endogenous virus sequences in normal cells appear to be associated with cell sequences reiterated 1200 times, and each integration unit is approximately equal to one 35s rna subunit. in amv-infected cells, the additional amv-specific dna sequ ... | 1975 | 169002 |
| lysine trna's associated with avian myeloblastosis virus 70s rna. | the lysine trna released from the 70s rna of avian myeloblastosis virus was separated by reversed-phase chromatography. all of the aag-coding lysine trna's were present in the 70s-associated fraction; however, the aaa-coding lysine trna could not be detected. chromatography of the lysine trna released at various temperatures did not show any preferential release of one aag-coding species over another. | 1976 | 183025 |
| amv rna transcription in cell-free systems and properties of in vitro chromatin-directed rna synthesis. | in this report we have presented evidence that viral sequences in the genome of amv-infected myeloblasts can be transcribed in vitro. the rna products synthesized in either nuclei isolated from these cells or by eukaryotic rna polymerase b from the isolated chromatin contained approximately 1% virus-specific sequences. this result, which is in agreement with the fraction of viral rna in infected cells (garapin et al. 1971), is higher than expected from a random transcription of the genome, and t ... | 1975 | 169005 |
| synthesis of avian rna tumor virus structural proteins. | | 1975 | 169008 |
| quantitative and qualitative differences in dna complementary to avian myeloblastosis virus between normal and leukemic chicken cells. | hybridization of avian myeloblastosis virus (amv) rna with dna immobilized on filters or in liquid with a vast dna excess was used to measure the viral specific dna sequences in chicken cells. newly synthesized viral dna (v-dna) appears within an hour after infection of chicken embryo fibroblasts (cef) with avian oncornaviruses. a fraction of newly synthesized v-dna becomes integrated into the cellular genome and the remainder gradually disappears. a covalent linkage between v-dna and cellular d ... | 1975 | 169823 |
| generation of avian myeloblastosis virus structural proteins by proteolytic cleavage of a precursor polypeptide. | | 1975 | 170408 |
| template recognition and chain elongation in dna synthesis in vitro. | | 1976 | 185394 |
| synthesis of the precursor to avian rna tumor virus internal structural proteins early after infection. | | 1976 | 185796 |
| acquisition of viral dna sequences in target organs of chickens infected with avian myeloblastosis virus. | the distribution of oncornavirus dna sequences in various tissues of normal chickens and of chickens with leukemia or kidney tumors induced by avian myeloblastosis virus (amv) was analyzed by dna-rna hybridization using 35s amv rna as a probe. all the tissues from normal chickens which were tested contained the same average cellular concentration of endogenous oncornavirus dna. in contrast, different tissues from lekemic chickens and from chickens bearing kidney tumors contained different concen ... | 1975 | 170415 |
| nonspecific immunosuppression and expression of avian myeloblastosis virus (bai strain a). | chickens were treated with cyclophosphamide in order to induce nonspecific immunosuppression. treated and untreated animals were injected with avian myeloblastosis virus (amv) or myeloblasts at the age when a pronounced resistance to the disease is observed. chickens treated with cyclophosphamide and then challenged with amv developed acute myeloblastic leukemia in 70 percent. similarly treated chickens transplanted with fresh amv producing myeloblasts exhibited 30 percent incidence of myeloblas ... | 1976 | 187971 |
| electrophoretic mobilities of rna tumor viruses. studies by doppler-shifted light scattering spectroscopy. | we have used laser beat frequency light scattering spectroscopy to measure, at several ph values, the electrophoretic mobilities of purified avian myeloblastosis (amv), murine leukemia (mulv), murine mammary tumor (mumtv), and feline leukemia (felv) viruses. the mobilities of these viruses are similar at ph greater than or equal to7 (-2.7 to -3.2 x 10(-4) (cm/sec)/(v/cm). the isoelectric points of mulv and amv are apparently less than ph 3, whereas for felv the data could be interpreted to indic ... | 1975 | 170961 |
| the oncornavirus maturation process: quantitative correlation between morphological changes and conversion of genomic virion rna. | avian myeloblastosis virus (amv) was harvested at different time intervals from chick leukemic myeloblasts, and the rate of the maturation process of amv was estimated on the basis of morphological changes in the virions and conversion of genomic viral rna. the change from immature virions characterized by the presence of an electronlucent center to the condensed mature form (with dense nucleoid) was accompanied by the conversion of 30-40s rna to 60s rna. both processes were quantitatively defin ... | 1976 | 188781 |
| inactivation of avian myeloblastosis virus dna polymerase by specific binding of pyridoxal 5'-phosphate to deoxynucleoside triphosphate binding site. | avian myeloblastosis virus (amv) dna polymerase is inactivated by preincubation with pyridoxal 5'-phosphate. this inactivation is relatively specific since various pyridoxal-5'-p analogs cause no inactivation. this effect is reversible but can be made irreversible by reduction with sodium borohydride; the reduced pyridoxal-5'-p adduct exhibits a new absorbance maximum at 325 nm and a fluorescence emission at 392 nm when excited at 325 nm. the evidence presented suggests the formation of a schiff ... | 1977 | 190232 |
| correlation of apparent molecular weight and antigenicity of viral proteins: an sds-page separation followed by acrylamide-agarose electrophoresis and immunoprecipitation. | a simple method is described which combines a sodium dodecyl sulfate polyacrylamide gel electrophoresis (sos-page) in the first demension with a second electrophoresis, at right angles to the first, into an agarose matrix. the proteins, separated by sds-page, are exposed to appropriate antisera after the second stage electrophoresis and immunoprecipitates form in the agarose corresponding to the relative electrophoretic mobilities of proteins in the first stage sds-page separation. the method th ... | 1977 | 190321 |
| characterization of tumour virus proteins. i. radioimmunoassay of the p27 protein of avian viruses. | the major structural protein of avian oncornaviruses, a core component of about 27000 daltons, has been measured by radioimmunoassay. the purified protein was labelled with 125iodine by chloramine-t method. the immune serum titer was defined as the highest serum dilution able to precipitate 50% of the labelled antigen present in the system. standard competition curve was constructed in order to determine the equivalents of protein, in a system with limiting antibody concentration. in the experim ... | 1977 | 190652 |
| partial purification and characterization of dna polymerases from a rous sarcoma virus-transformed rat cell line. | a new dna polymerase was partially purified from cell-free extracts of a continuous rat cell-line (xc). the xc cells had been transformed by the prague strain of rous sarcoma virus but did not produce infectious virus. the molecular weight of the dna polymerase is 70,000, as estimated by glycerol gradient centrifugation and by sephadex gel filtration. this enzyme can be distinguished from the other cellular dna polymerases by its elution pattern on dna-cellulose column chromatography, its molecu ... | 1975 | 170987 |
| synthesis of viral proteins by the avian myeloblastosis viral core component. | avian myeloblastosis viral (amv) core component was isolated and shown to synthesize amv proteins in vitro. this reaction was linearly dependent on viral core concentration, proceeded linearly with time, and was inhibited by puromycin and aurintricarboxylic acid. the proteins synthesized in vitro co-electrophoresed and co-chromatographed with known proteins, and were immunoprecipitated by total and monospecific antibodies to known amv proteins. | 1975 | 170991 |
| preparation of antisera to group-specific antigens of avian leukosis-sarcoma viruses: an alternate approach. | immunization of rabbits with a pooled preparation of chromato-graphically purified avian myeloblastosis virus (amv) group-specific (gs) antigens produced relatively large volumes of antiserum that was as broadly reactive in complement-fixation (cf) tests as antiserum produced in hamsters with tumors induced by rous sarcoma virus. this alternate procedure should be of value for routine preparation of leukosis virus gs antiserum. other antisera prepared against disrupted amv had spurious reactivit ... | 1977 | 194573 |
| analysis of oncornavirus rna subunits by electron microscopy. | subunits of oncornavirus (avian myeloblastosis virus) rna were isolated from purified 60--70s viral rna by heat dissociation. molecules sedimenting at 35 s, assumed to be the major component of the viral genome, were visualized in the electron microscope and their lengths were statistically analyzed. the results indicate a rather heterogeneous population of molecules with five distinct, reproducible size groups, an observation that excludes the assumption of random degradation of the genome. in ... | 1975 | 171673 |
| avian myeloblastosis virus dna polymerase. kinetic studies on the incorporation of noncomplementary nucleotides. | the high error rate characteristic of dna polymerases from rna tumor viruses has permitted measurements on the simultaneous incorporation of complementary and noncomplementary nucleotides during dna synthesis. for example, avian myeloblastosis virus dna polymerase incorporates 1 molecule of dcmp for approximately 500 molecules of dtmp polymerized using polyriboadenylic acid as a template. the parallel incorporation of complementary and noncomplementary nucleotides afer gel filtration of avian my ... | 1975 | 172498 |
| homology between avian oncornavirus rnas and dna from several avian species. | 3h-labeled 35s rna from avian myeloblastosis virus (amv), rous associated virus (rav)-0, rav-60, rav-61, rav-2, or b-77(w) was hybridized with an excess of cellular dna from different avian species, i.e., normal or leukemic chickens, normal pheasants, turkeys, japanese quails, or ducks. approximately two to three copies of endogenous viral dna were estimated to be present per diploid of normal chicken cell genome. in leukemic chicken myeloblasts induced by amv, the number of viral sequences appe ... | 1975 | 172655 |
| ribonucleotide sequence homology among avian oncornaviruses. | rna sequence relatedness among avian rna tumor virus genomes was analyzed by inhibition of dna-rna hybrid formation between 3h-labeled 35s viral rna and an excess of leukemic or normal chicken cell dna with increasing concentrations of unlabeled 35s viral rna. the avian viruses tested were rous associated virus (rav)-3, avian myeloblastosis virus (amv), rav-60, rav-61, and b-77 sarcoma virus. hybridization of 3h-labeled 35s amv rna with dna from normal chicken cells was inhibited by unlabeled 35 ... | 1975 | 173876 |
| rate of virus-specific rna synthesis in synchronized chicken embryo fibroblasts infected with avian leukosis virus. | the rate of avian leukosis virus (alv)-specific rna synthesis has been examined in bot- uninfected and alv-infected synchronized chicken embryo fibroblasts. rna from cells labeled for 2h with [3h]uridine was hybridized with avian myeloblastosis virus poly(dc)-dna, and the hybridized rna was analyzed with poly(i)-spephadex chromatography. approximately 0.5% of the rna synthesized in alv-infected cells was detected as virus specific, and no more than a twofold variation in the rate of synthesis wa ... | 1976 | 176421 |
| frog oocytes synthesize and completely process the precursor polypeptide to virion structural proteins after microinjection of avian myeloblastosis virus rna. | after microinjection of xenopus laevis oocytes with rna from avian myeloblastosis virus, viral structural proteins p27, p19, p15, and p12 are formed by a sequence of posttranslational cleavages of a high-molecular-weight precursor polypeptide. the 60-70s rna aggregate or its 30-40s rna subunits obtained by heat or formamide treatment possess the same ability to serve as template in x. laevis oocytes. the processing pattern of virus-specific precursor polypeptides is the same in x. laevis oocytes ... | 1977 | 198776 |
| renal neoplastic response to leukosis virus strains bai a (avian myeloblastosis virus) and mc29. | previous reports described the induction of avian renal neoplasms by leukosis virus strains bai a [avian myeloblastosis virus (amv)] and mc29, and illustrated morphological characteristics of the tumors. continued studies in this work confirm evidence of the origin of the tumors from embryonal cells residual in the posthatched chick. the work further emphasizes differences in histopathology of the neoplasms caused by the two viruses and reveals differences in the histopathogenesis of the respect ... | 1976 | 177194 |
| avian leukosis-sarcoma virus gene expression. noncoordinate control of group-specific antigens in virus-negative avian cells. | | 1976 | 178098 |
| identification of dna in the core component of avian myeloblastosis virus. | avian myeloblastosis virus (amv) was found to contain dna associated with the virion. the viral envelope was removed by treating the virus with a nonionic detergent and the dna was found in the core fraction. these experiments indicate that the dna associated with tumor virus is not contaminant associated with the viral envelope and suggest that the dna is part of the internal core component. the dna from avian myeloblastosis virus has a density of 1.70 g/cm3. | 1976 | 178377 |
| nucleic acid renaturation and restriction endonuclease cleavage analyses show that the dnas of a transforming and a nontransforming strain of epstein-barr virus share approximately 90% of their nucleotide sequences. | viral dna molecules were purified from a nontransforming and a transforming strain of epstein-barr virus. each viral dna was labeled in vitro and renatured in the presence of an excess of either one or the other unlabeled viral dna. both viral dnas were also digested with the eco r1 restriction endonuclease and subsequently labeled by using avian myeloblastosis virus dna polymerase to repair either the ecor1 nuclease-generated single-stranded ends of the dnas or their single-stranded ends produ ... | 1976 | 178907 |
| evidence for tandem integration of avian myeloblastosis virus dna with endogenous provirus in leukemic chicken cells. | the integration site of avian myeloblastosis virus (amv) proviral dna in dna from leukemia chicken myeloblasts has been studied by three sequential nucleic acid hybridizations that can localize the proviral dna according to the repetitiveness of the adjacent cellular dna regions. first, large denatured cellular dna fragments (2.1 x 10(6) daltons) were reassociated and fractionated according to sequence reiteration frequenct. next, dna remaining single-stranded in each fraction was immobilized on ... | 1976 | 179099 |
| hydrophobic interaction of retroviral dna polymerases with alkyl-agarose matrices. | | 1978 | 203279 |
| size and secondary structure of avian myeloblastosis virus associated ribosomal rna: comparison with cellular and precursor ribosomal rna. | ribosomal rna isolated from ribosomes present inside avian myeloblastosis virus (amv) was characterized by electron microscopy using the formamide-urea spreading technique. the molecular weight and the secondary structures were compared with those of r-rna and precursor r-na isolated from host cells, the leukemic myeloblasts. the molecular weight of viral r-rna (1.62 +/- 0.18 x 10(6) and 0.69 +/- 0.10 x 10(6)) and the molecular weight of cellular r-rna (1.63 +/- 0.18 x 10(6) and 0.67 +/- 0.09 x ... | 1978 | 205195 |
| in vitro transcription of reconstituted 35s rna.trnatrp template.primer complexes by the avian oncornavirus dna polymerase. effect of temperature on the size of the dna transcripts. | | 1978 | 206008 |
| avian myeloblastosis virus-induced lymphosarcoma producing erythroblastic leucosis in chicks. | acute myeloblastosis and several forms of tumor, including one case of lymphosarcoma occurred when avian myeloblastosis virus (bai-a strain) was inoculated into newly hatched chicks (spf). the homogenate of lymphosarcoma inoculated intraperitoneally into other newly hatched chicks induced a high incidence of erythroblastic leucosis. electron microscopy did not reveal the presence of c-type virus particles in the tumor tissue. the relationship between avian myeloblastosis virus, lymphosarcoma and ... | 1975 | 179285 |
| separation of time-defined avian myeloblastosis virus (amv) using column cultivation of leukaemic myeblasts. | a new technique is described of column cultivation of cells immobilized on sial glass cullet. the technique ensures a controlled and continuous production of time-defined young virus. during the column cultivation the morphological characteristics of tho immobilized cells remain essentially unchanged. | 1976 | 179904 |
| biochemical properties of avian type-c virus gag gene-coded proteins: comparison with structural proteins coded for at analogous positions within the mammalian type-c viral genome. | | 1978 | 208245 |
| the influence of carbohydrate on the antigenicity of the envelope glycoprotein of avian myeloblastosis virus and b77 avian sarcoma virus. | | 1978 | 208246 |
| genome organization of rna tumor viruses. i. in vitro synthesis of full-genome-length single-stranded and double-stranded viral dna transcripts. | genome-length complementary dna (cdna) transcripts were synthesized in vitro by using purified virions of avian myeloblastosis virus. moloney murine leukemia virus, and clone 124 mouse sarcoma virus. the size of the genomelenth cdna transcripts was measured on either alkaline sucrose gradients or alkaline agarose gels. the longest cdna transcripts synthesized by using avian myeloblastosis virus, moloney murine leukemia virus, and clone 124 mouse sarcoma virus were 7, 9 and 6 kilobases (kb), resp ... | 1978 | 209213 |
| a cell-free mammalian protein-synthesizing system stimulated by rna from avian myeloblastosis virus. | carcinoma cells, oncornavirus-infected cells and fetal bovine tissue provide salt wash ribosomal factors capable of responding to avian myeloblastosis virus (am virus)-rna and stimulating the incorporation of amino acids into proteins as well as catalyzing the binding of n-acetylated (35s) methionyl-trna. the exogenously dependent amino acid incorporation system is stimulated by the high molecular weight species of am virus-rna only, particularly the fraction containing polyadenylate (poly(a)) r ... | 1975 | 167845 |
| a 32,000-dalton nucleic acid-binding protein from avian retravirus cores possesses dna endonuclease activity. | | 1978 | 210568 |
| isolation of the proviral coding strand of avian myeloblastosis virus from leukemic chicken myeloblast by affinity chromatography. | | 1978 | 210689 |
| stepwise transition of aggregate structure of high-molecular-weight avian myeloblastosis virus rna. mode of releasing of associated 4s rna. | mode of releasing of associated 4s rna species was studied during a controlled transition of aggregate structure of high-molecular-weight amv-rna. it has been found that associated 4s rna constitutes 2.5% of 60s amv-rna complex. approximately 60% of associated 4s rna is successively released during treatment of viral rna with increasing formamide concentration, concomitantly with the transition of 60s rna aggregate through 50--55s rna intermediate into the final 30--40s rna subunits. 40% of 4s r ... | 1976 | 180440 |
| base sequence complexity of 35s avian myeloblastosis virus rna determined by molecular hybridization kinetics. | | 1975 | 169041 |
| genetic analysis of the defectiveness in strain mc29 avian leukosis virus. | | 1978 | 211711 |
| cap analogues do not inhibit mrna translation in xenopus laevis oocytes. | | 1978 | 212317 |
| polypeptides isolated from ribosome-like structures occluded in avian myeloblastosis virus (amv). | the protein composititon of ribosome-like particles isolated from amv was determined by acrylamide gel electrophoresis and by immunological methods. it was established that the protein spectrum of ribosome-like particles differed significantly form the total protein spectrum of amv. the most characteristic protein components of ribosome-like particles had a molecular weight in the range of 70 000--110 000. apart from these proteins, the viral ribosomal particles contained a small amount of prot ... | 1975 | 169489 |
| virus-infected avian cell lines established in vitro. | four virus-infected avian cell lines have been established in culture. two of these lines, infected with bai strain a virus, liberate only small quantities of virus in the culture fluid. the cells retain the ability to induce myeloblastic leukemia when inoculated i.v. into 1- to 2-day-old chicks, but do so less efficiently than freshly obtained myeloblasts. these cells do not appear to be transplantable, since the disease produced is characterized by the presence of myeloblasts that liberate lar ... | 1976 | 184918 |
| the inhibition of rauscher leukemia virus and avian myeloblastosis virus dna polymerases by anthracycline compounds. | studies by other investigators have shown that adriamycin and daunorubicin exhibit antitumor and antiviral activity. a possible antiviral mechanism for the anthracycline compounds is the potent inhibition of viral dna polymerases. five anthracycline compounds were tested against purified rauscher leukemia virus and avian myeloblastosis virus dna polymerases. all compounds were found to be potent inhibitors of viral dna polymerase activity. inhibition was found to be primarily due to the planar r ... | 1977 | 212987 |
| expression of viral proteins in mammalian cells transformed by avian sarcoma viruses. | the expression of viral proteins in nine lines of hamster and rat cells transformed by avian sarcoma viruses (asv) was studied by indirect immunofluorescence with monospecific antisera to purified gp85 and p27 of amv-b and a polyvalent antiserum to all the p proteins of this same virus. the lines of asv-transformed cells were either low virus producers (vp) or inducible or non-inducible non producers (np). cytoplasmic expression of p proteins was observed in all the cell lines except the least i ... | 1976 | 186419 |
| characterization of an adenosine triphosphatase of the avian myeloblastosis virus and the virus-infected myeloblast. | | 1978 | 214398 |
| restricted addition of proviral dna in target tissues of chickens infected with avian myeloblastosis virus. | proviral dna is synthesized within an hour after infection of chicken cells with an avian oncornavirus and is integrated into nuclear cellular dna within a short time. the viral dna appears to be synthesized as double-stranded molecules of approximately 6 x 10(6) daltons some of which are converted into supercoiled cricles perhaps as a requisite for integration. the endogenous v-dna in normal chicken cells and both the endogenous and amv v-dna in leukemic chicken myeloblasts are covalently linke ... | 1976 | 188728 |
| homogeneity and complexity of avian oncornavirus proviral dna determined by molecular hybridization. | the homogeneity of dna complementary to the 35s rna subunit of avian myeloblastosis virus (amv) has been demonstrated by single or multistep hybridization. for multistep hybridizations, 35s amv rna was preselected for its ability to hybridize either to unfractionated leukemic dna or to leukemic dna enriched for unique or for reiterated sequences. these experiments indicate that the viral genome is complementary to dna sequences with a low reiteration frequency. competition experiments confirm th ... | 1977 | 191654 |
| translation of alfalfa-mosaic-virus rna 1 in the mrna-dependent translation system from rabbit reticulocyte lysates. | translation of alfalfa mosaic virus (amv) rnas in the mrna-dependent rabbit reticulocyte cell-free system was examined using different rna concentrations. the pattern of products synthesized under the direction of amv rna 2, 3 and 4 was not or almost not influenced by their concentration. however, depending on the rna 1 concentration either a very large protein of mr 115,000 or a mixture of two smaller proteins, mr 58,000 and 62,000 respectively, was formed. these three proteins represent overla ... | 1979 | 217681 |
| selection of methionine trnas by avian oncornaviruses. | the free 4s rna of avian rna tumor viruses is greatly enriched in one of the four methionine trnas of the host cells, trna4met. on the assumption that viral trnamet forms are identical to the corresponding trnas of mouse or chick cells, the following conclusions were drawn concerning the trnamet content of oncornaviruses: (1) trnamet species may be compartmentalised within the host cells, and the viral trna pool could reflect the cellular compartment in which viral maturation takes place since t ... | 1978 | 218169 |
| interspecies homology of rna tumor virus proteins. | we report the application of a highly sensitive column chromatographic technique to the comparison of tryptic peptide maps of some rna tumor virus proteins. by combining microbore ion-exchange chromatography with a sensitive fluorescent assay using o-phthalaldehyde, we obtained high-resolution peptide maps starting with only microgram amounts of protein. our discovery of coincident peptides from the 15,000 and 30,000 molecular weight proteins from murine and feline leukemia viruses supports sero ... | 1977 | 193551 |
| biological characterization of avian osteopetrosis. | chicks infected as 12-day-old embryos with an end-point purified derivative of avian myeloblastosis virus developed a rapidly progressive osteopetrosis that manifested within 1 week of hatching. a detailed comparison of osteopetrotic chicks and normal hatchmates revealed the following. (i) osteopetrotic chicks exhibited a stunting syndrome, growing at a mean rate that was 26% of the control rats. (ii) at autopsy, the mass of the lymphoid organs was reduced, whereas the mass of the heart, pancrea ... | 1977 | 197009 |
| solubilization, purification, and characterization of a nucleoside triphosphatase from avian myeloblastosis virus. | | 1977 | 197100 |
| dna endonucleases associated with the avian myeloblastosis virus dna polymerase. | a dna endonuclease, endo-i, which cleaves superhelical dnas, has been isolated from avian myeloblastosis virions stripped of their coats by mild detergent treatment. the enzyme has a broad ph optimum around 7.5-8.0 and requires mg2+ for activity. a second endonuclease, endo-ii, with a requirement for mn2+, also present in viral cores, copurified with avian myeloblastosis virus alpha beta dna polymerase (reverse transcriptase, rna-dependent dna nucleotidyltransferase) and similarly cleaved superh ... | 1979 | 223153 |
| stimulation of sugar uptake and glycolysis in chicken embryo fibroblasts by the major glycoprotein from avian myeloblastosis virus. | addition of purified major glycoprotein from avian myeloblastosis virus to growing or quiescent chicken embryo fibroblasts rapidly stimulates the rate of hexose transport and increases the lactic acid production. these stimulatory effects are dependent on the time of exposure and the dose of viral glycoprotein. in contrast, the glycoprotein only marginally affects hexose transport in chicken cells transformed by rous sarcoma virus. some effects of the glycoprotein on serum-starved quiescent cell ... | 1979 | 223157 |
| interaction of oncornaviral proteins separated by sds-page with antibodies in immunodiffusion. | | 1977 | 197437 |
| search for virus specific dna sequences and viral particles in mitochondria of avian leukemic myeloblasts. | the intracellular localization of the avian myeloblastosis virus (amv) genome was studied. nuclear and mitochondrial dnas from myeloblasts were examined by hybridization with 32p labeled amv-rna of high molecular weight for the presence of virus specific dna sequences. nuclear dna (ndna) from myeloblasts specifically hybridized with viral rna, whereas purified closed circular mitochondrial dna (mtdna) did not hybridize with viral rna. it was therefore concluded that viral genome was present in n ... | 1977 | 197796 |
| avian myeloblastosis virus rna is terminally redundant: implications for the mechanism of retrovirus replication. | we have determined the terminal heteropolymeric sequences of amv rna by the following procedures: first, rna sequence determination on the 5' terminal and the poly(a)-linked 3' terminal t1 oligonucleotides, and second, analysis by the maxam and gilbert (1977) method of amv strong stop dna and of dna complementary to the poly(a)-linked t1 oligonucleotide, synthesized with reverse transcriptase and (pdt)13 as primer. the structure deduced for the 5' terminal region is (5')7mgpppgmccauucuaccucucacc ... | 1977 | 198142 |
| partial purification and characterization of a ribonucleic acid n2-guanine methyltransferase associated with avian myeloblastosis virus. | a nucleic acid methylase, n2-guanine ribonucleic acid (rna) methyltransferase, which is associated with type c rna tumor viruses, has been purified from avian myeloblastosis virions by gel filtration on sephadex g-200, followed by chromatography on hydroxylapatite. the molecular weight estimated by gel filtration is 220 000, and the methylase activity has a ph optimum of 7.6--7.9. magnesium and ammonium ions both stimulate activity 1.5-fold at 9.5 mm and 0.36 m, respectively, but apparently neit ... | 1979 | 227452 |
| single-stranded dna from oncornavirus-infected cells enriched in virus-specific dna sequences. | we previously found that a minor fraction of single-stranded dna (ss-dna) isolated from native nuclear dna of normal chicken embryonic cells and cells of other species hybridized with bulk nuclear dna or cellular rna in great excess. at least one-third of ss-dna belonging to the nonrepetitious part of the cell genome could be hybridized to homologous rnas. in the present work, similar results were obtained with ss-dna from cells of chickens infected by avian myeloblastosis virus (amv). to invest ... | 1977 | 198800 |
| [cellular contaminants and structural proteins of rous sarcoma virus (rsv), studied by polyacrylamide gel electrophoresis]. | the number of polypeptides in highly purified preparations of rsv, of two different subgroups, produced in culture, has been compared to the polypeptides present in the supernatant of uninfected cultures and processed in identical manner. the analysis of page-sds shows that from 13 to 18 polypeptides present in viral preparations may be cellular contaminants. fewer contaminating polypeptides are found in the myeloblastosis virus purified from plasma of chicken. | 1977 | 199367 |
| measurement of proviral genes in uninfected and avian myeloblastosis virus-infected cells by hybridization with 3h-labeled complementary dna probe excess. | viral rna (vrna) from avian myeloblastosis virus or dna from virus-infected and uninfected cells was hybridized with [3h]dna complementary to viral rna ([3h]cdna) under conditions of [3h]cdna excess. when [3h]cdna was used to drive the hybridization reaction with vrna, a rate constant of 33.2 liters/mol-s was obtained. the same rate constant was obtained when vrna excess was used as the driver. the specific activities of the [3h]dna probe, estimated from kinetic measurements of the hybridization ... | 1977 | 199736 |
| an enzyme-linked immunosorbent assay for detecting avian leukosis-sarcoma viruses. | immunoglobulins from antiserum raised against chromatographically purified avian myeloblastosis virus (amv) group-specific (gs) antigens were used in enzyme-linked immunosorbent assay (elisa). readily discernible color was produced with 2--3 ng of amv protein in microplate wells coated with 4 micrograms of salt-precipitated immunoglobulins. when a biological assay, i.e., phenotypic mixing (pm), was the criterion for the infectious status of specimens, the elisa consistently identified a greater ... | 1979 | 230808 |