Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| effect of endogenous leukosis virus genes on response to infection with avian leukosis and reticuloendotheliosis viruses. | we examined the effect of the presence or absence of endogenous viral gene (ev) 3, which controls expression of group-specific viral and envelope antigens (gs+chf+ phenotype), and ev2, which controls the production of a complete subgroup e virus (v-e+ phenotype), on the response of chickens to rav-1, an exogenous avian leukosis virus (alv) with an antigenic relationship to endogenous virus. after inoculation at one day of age, the chickens lacking either ev gene expression had a lower frequency ... | 1982 | 6285878 |
| sequence of the long terminal repeat and adjacent segments of the endogenous avian virus rous-associated virus 0. | rous-associated virus 0 (rav-0), an endogenous chicken virus, does not cause disease when inoculated into susceptible domestic chickens. an infectious unintegrated circular rav-0 dna was molecularly cloned, and the sequence of the long terminal repeat (ltr) and adjacent segments was determined. the sequence of the ltr was found to be very similar to that of replication-defective endogenous virus ev-1. like the ev-1 ltr, the rav-0 ltr is smaller (278 base pairs instead of 330) than the ltrs of th ... | 1982 | 6286997 |
| studies of avian leukosis virus infection in chickens from a commercial breeder flock. | progeny chicks from a commercial breeder flock with a high rate of avian leukosis virus (alv) infection were classified as congenitally or contact infected with alv on the basis of virus tests on their meconia at hatching and the presence or absence of antibodies at 20 weeks of age. the alv infection profile, shedding, tumor mortality, and egg production in the congenitally-infected chickens were compared with those in the contact-infected hatchmates. results show that viremic-tolerant hens clas ... | 1982 | 6287446 |
| common proviral integration sites in c57bl mouse lymphomas induced by radiation leukemia virus and absence of novel virus-related sequences in radiogenic lymphoma dna. | three c57bl/ka mice were inoculated with radlv/vl3, a thymotropic and leukemogenic virus population released by the permanent bl/vl3 cell line, which was derived from a c57bl/ka lymphoma induced by radiation leukemia virus (radlv). the neoplastic thymus and bone marrow cells from these mice were grown until the cultures became permanently established, and their dnas were examined for the presence of virus-related sequences by restriction enzyme analysis. all six cell lines displayed identical ec ... | 1982 | 6289014 |
| isolation of 16l virus: a rapidly transforming sarcoma virus from an avian leukosis virus-induced sarcoma. | we have isolated a replication-defective rapidly transforming sarcoma virus (designated 16l virus) from a fibro-sarcoma in a chicken infected with td107a, a transformation-defective deletion mutant of subgroup a schmidt-ruppin rous sarcoma virus. 16l virus transforms fibroblasts and causes sarcomas in infected chickens within 2 wk. its genomic rna is 6.0 kilobases and contains sequences homologous to the transforming gene (fps) of fujinami sarcoma virus (fsv). rnase t1 oligonucleotide analysis s ... | 1982 | 6289331 |
| characterization of c-lil, a chicken cellular sequence associated with a stock of b77 avian sarcoma virus. | using biochemical methods, we have shown that a new specific sequence, v-lil, is associated with a given stock of b77 avian sarcoma virus (clone 9). we prepared a dna complementary to v-lil sequences, using substractive hybridizations, and investigated the properties of this sequence. v-lil has a genetic complexity of ca. 2,000 nucleotides and is not present in various stocks of avian sarcoma virus, avian leukosis virus, or defective leukemia virus. v-lil is not associated with b77 avian sarcoma ... | 1982 | 6292471 |
| orientation and position of avian leukosis virus dna relative to the cellular oncogene c-myc in b-lymphoma tumors of highly susceptible 15i5 x 7(2) chickens. | we previously reported our characterizations of the b-lymphoma tumors induced in a highly susceptible line of chickens (15i5 x 7(2)) by the avian leukosis virus rav-1 (proc. natl. acad. sci. 78:3418-3422, 1981). we demonstrated that in greater than 90% of the tumors, the rav-1 provirus is integrated near a cellular oncogene, c-myc. in the present study, we devised a simple approach, relying on sali digestion, for further defining the locations and orientations of the proviruses with respect to t ... | 1982 | 6292531 |
| effect of intron size on splicing efficiency in retroviral transcripts. | to study the effect of intron size on splicing efficiency we have varied the size of the avian leukosis virus (alv) env mrna intron in a cloned alv genome. this was accomplished by deletion of alv sequences or insertion of phage lambda dna. the effect of these modifications on splicing was analyzed by microinjection of the modified clones into rsv(-) chicken cells. viral env mrna when transcribed and properly spliced within these cells complemented the rsv(-) env deficiency leading to the produc ... | 1982 | 6292870 |
| pathogenicity of avian leukosis viruses. | three methods were used in attempts to obtain non-oncogenic avian leukosis virus for possible use as an immunoprophylactic agent for the control of lymphoid leukosis in chickens. these were: 1) isolate a nononcogenic virus from commercial breeder flocks experiencing very little or no lymphoid leukosis; 2) obtain a non-oncogenic recombinant from mixed infection of a strain with low oncogenicity, rous-associated virus-60 (rav-60), with rav-1 or rav-2 in cell culture; and 3) attempt to attenuate su ... | 1982 | 6293446 |
| the effectiveness of selection for reduced avian leukosis virus shedding in different chicken strains. | 1982 | 6293449 | |
| age related resistance to avian leukosis virus. ii. influence of age at inoculation on mortality and congenital transmission. | six age groups of specified pathogen free white leghorn chickens housed in the same filtered air, positive pressure building, were inoculated at 1 day, 2, 4, 6, 8 and 10 weeks of age respectively, with a mixture of leukosis viruses of subgroups a and b. birds which died during the experiment were examined for gross and microscopical lesions. the incidence of lymphoid leukosis (ll) in the various groups was inversely proportional to the age of first virus exposure, le., mortality was 62.5% in the ... | 1982 | 18770176 |
| age related resistance to avian leukosis virus. iii. infectious virus, neutralising antibody and tumours in chickens inoculated at various ages. | viraemia and neutralising antibodies were determined in chickens of six age-groups following inoculation with leukosis virus of subgroups a and b at the age of 1 day, and 2, 4, 6, 8 and 10 weeks respectively. the birds were kept in a filtered air positive pressure (fapp) house. a seventh age-group, accommodated in a separate fapp-house, was used as an untreated control. serum samples, received at biweekly intervals between 1-17 weeks post-inoculation, from birds of the groups inoculated at 4, 6, ... | 1982 | 18770194 |
| comparative response of turkeys and chickens to avian lymphoid leukosis virus. | response of turkeys and 151(5)x7(1) chickens to prenatal or neonatal inoculation with the avian leukosis virus rav-1 was compared. virus-inoculated turkeys and chickens developed viraemia and antibody to. rav-1. many of the chickens remained persistently viraemic through the duration of the experiment, whereas in turkeys viraemia was transient. circulating antibodies were detected earlier in turkeys than in chickens. inoculation of turkeys with rav-1 resulted in a high incidence of inflammatory ... | 1983 | 18766780 |
| neoplasms in budgerigars (melopsittacus undulatus): clinical, pathomorphological and serological findings with special consideration of kidney tumours. | according to findings of others and to our own investigations, kidney tumours represent a remarkably high proportion of all tumours in budgerigars. therefore, 74 budgerigars, clinically suspicious for abdominal tumours, were analysed individually by monitoring clinical signs, gross lesions, histology, the expression of the group-specific (gs) antigen of avian leukosis virus (alv), the expression of immunoglobulins m and g, and the distribution of age and tumour incidence. lameness and abdominal ... | 1983 | 18766792 |
| the use of elisa for detection of exogenous and endogenous avian leukosis viral antigens in basic breeding flocks. | an enzyme-linked immunosorbent assay (elisa) for avian leukosis/ sarcoma virus (alv) group-specific (gs) antigens was used to study the identification of hens which congenitally excrete exogenous alv. the sensitivity of this assay was compared with that of the phenotypic mixing test (pmt) and the direct complement fixation test (cft) by testing limiting dilutions of purified avian myeloblastosis virus (amv), embryo homogenates and albumens. about 0.4 ng/ml of purified amv protein could be detect ... | 1983 | 18766804 |
| comparison of the oligosaccharide moieties of the major envelope glycoproteins of the subgroup a and subgroup b avian myeloblastosis-associated viruses. | the nature of the oligosaccharide chains of the major envelope glycoprotein, gp85, from avian myeloblastosis-associated viruses has been examined for the subgroup a and subgroup b viruses replicated in fibroblasts from the same chicken embryos. pronase-digested glycopeptides from [3h]mannose- or [3h]glucosamine-labeled viruses were analyzed by the combined techniques of gel filtration, endo-beta-n-acetylglucosaminidase digestion, and concanavalin a affinity chromatography. the gp85 protein from ... | 1983 | 6296432 |
| identification and nucleotide sequence of a human locus homologous to the v-myc oncogene of avian myelocytomatosis virus mc29. | avian myelocytomatosis virus mc29 is a replication-defective acute leukaemia virus which induces a variety of tumours in chickens including sarcomas, renal and hepatic carcinomas, and myelocytomatosis. the oncogenic potential of the virus is mediated by the gene v-myc, acquired from sequences (c-myc) present in normal uninfected chicken dna. sequences closely related to chicken c-myc have been highly conserved throughout evolution, from drosophila to vertebrates. the hypothesis that c-myc may be ... | 1983 | 6298632 |
| induction of angiosarcomas by ring-necked pheasant virus. | ring-necked pheasant virus, an avian leukosis virus, when injected into 10-day old chick embryos, caused angiosarcomas in the lungs of infected chickens within a short time. angiosarcomas appeared as localized foci of proliferating cells in the lungs as early as 2 weeks posthatch, and by 6 weeks, the lungs of the infected chickens were frequently filled with tumor cells. between 3 and 10 weeks of age, 80% of infected chickens died of the angiosarcomas; the 20% which lived 8 weeks or longer had s ... | 1983 | 6299960 |
| rapid induction of hypothyroidism by an avian leukosis virus. | infection of 10-day chicken embryos with an avian leukosis virus, rav-7, resulted in hypothyroidism within 3 weeks posthatching. histological examination of the thyroids from infected chickens showed an extensive infiltration of lymphoblastoid cells by 7 days posthatching. areas resembling germinal centers were present in the thyroids of infected chickens by 3 weeks posthatching. examination of circulating thyroid and pancreas hormones showed a significant reduction in t3 and t4 levels and a tre ... | 1983 | 6302005 |
| studies of reticuloendotheliosis virus-induced lymphomagenesis in chickens. | seventy-three percent of chickens inoculated with the chick syncytial strain of reticuloendotheliosis virus (rev) at hatching developed lymphomas by 39 weeks of age. neonatal treatment with cyclophosphamide or surgical bursectomy at 2, 4, 8, or 12 weeks of age significantly (p less than 0.01) reduced lymphoma development. in a further experiment, surgical bursectomy of rev-infected chickens followed by intravenous inoculation of the chickens with a single cell suspension of their own bursa cells ... | 1983 | 6303293 |
| activation of the cellular oncogene c-erbb by ltr insertion: molecular basis for induction of erythroblastosis by avian leukosis virus. | avian leukosis virus (alv), a slowly oncogenic retrovirus, induces in chickens a variety of neoplasms, including lymphoid leukosis and erythroblastosis. in lymphoid leukosis, a cellular oncogene, c-myc, is activated by the insertion of alv ltr. we provide evidence that alv utilizes a similar mechanism in erythroblastosis induction by activating a different cellular oncogene, c-erbb. we report the isolation, from leukemic erythroblast dna, of a clone that represents the viral-cell junction fragme ... | 1983 | 6305505 |
| b5 and b15 associated with progressive marek's disease, rous sarcoma, and avian leukosis virus-induced tumors in inbred 15i4 chickens. | rprl 15i4 inbred chickens are nearly histocompatible except for the b5 and b15 haplotypes that determine the major transplantation antigens. b5b5 and b15b15 15i4 chickens were equally and highly susceptible to tumors induced by marek's disease, rous sarcoma, or avian leukosis viruses (alv), suggesting both of these haplotypes may determine a general influence leading to tumor development. the 15i4 birds were highly susceptible to erythroblastosis, and most developed immunological tolerance to th ... | 1983 | 6306630 |
| viral sequences determining the oncogenicity of avian leukosis viruses. | our analyses of the sequence of the recombinant virus ntre7 and comparison with its endogenous and exogenous alv parents indicate that a section of approximately 400 base pairs at the 3' end of the genome encodes a function which is required for oncogenicity. this section includes an exogenous virus specific region (xsr) of approximately 148 base pairs and the u3 region of the ltr. at present it seems most likely that the function required for oncogenicity is the transcription promoter contained ... | 1983 | 6306683 |
| cancer induction by insertional mutagenesis: the role of viral genes in avian leukosis virus induced cancers. | 1983 | 6306689 | |
| immunological phenotype of lymphomas induced by avian leukosis viruses. | the production of immunoglobulin by six cell lines derived from bursal tumors induced by avian leukosis virus follows two general patterns: (i) three cell lines that have been extensively passaged in culture synthesize and secrete light chains only; (ii) three cell lines that are recently isolated produce and secrete monomeric immunoglobulin m in addition to free light chains. all six cell lines synthesize and secrete both glycosylated and unglycosylated forms of light chain. we conclude that th ... | 1983 | 6308424 |
| avian leukosis virus infection and congenital transmission in lines of chickens resisting selection for reduced shedding. | two lines (d and e) of three breeder lines of chickens that had resisted selection for reduced avian leukosis virus (alv) congenital transmission on the breeder's premises did not resist the same selection procedures (tests for gs-antigen in albumen) under laboratory conditions. the incidence of alv congenital transmission in the remaining third line (f) was spontaneously reduced from 13% to 0.9%. environmental alv exposure of uninfected chicks after hatching induced 7-10% of the progeny from li ... | 1983 | 6314970 |
| evidence that avian tumour virus-immune chicken sera recognize only viral structural antigens on the surface of avian tumour virus-infected cells. | the specificity of the humoral response of chickens to avian tumour viruses (atv) was investigated by reacting atv-immune sera with triton x-100 extracts of uninfected, infected and transformed chicken embryo fibroblasts. analysis of these immune reactions by polyacrylamide gel electrophoresis revealed that avian leukosis virus-challenged and rous sarcoma virus-challenged chickens recognized only two major cell surface antigens of 100000 and 29000 mol. wt. which were present on transformed and n ... | 1983 | 6315863 |
| incidence of avian leukosis virus infection in broiler stocks and its effect on early growth. | twenty-eight broiler breeder flocks were tested for avian leukosis virus (alv) group-specific (gs) antigen shedding into the albumen. the rate of shedding ranged from 0 to 17%, rates substantially lower than those observed previously in egg production stocks. the flock shedding at the highest rate was trap nested and dams positive and negative for gs antigen shedding in the albumen produced progeny for a growth trial. chicks produced by the positive and negative dams had 27 and 1% alv isolations ... | 1983 | 6322147 |
| monoclonal antibodies with specificity for three different serotypes of marek's disease viruses in chickens. | a total of 50 antibody-secreting hybridoma cells against marek's disease virus (mdv) and turkey herpesvirus (hvt) have been produced. eleven hybridomas were used for serotyping a panel of 15 pathogenic and nonpathogenic strains of mdv and hvt, representing three serotypes. the antibodies from the culture medium have fluorescence antibody (fa) titers of up to 100 and those from mouse ascitic fluid have titers ranging from 10(4) to 10(6). monoclonal antibody t81 is type-common, i.e., it reacts at ... | 1983 | 6184394 |
| using retroviruses as insertional mutagens to identify cellular oncogenes. | three criteria have been used to identify cellular genes that might play a role in oncogenesis: (i) homology with known viral transforming genes (v-onc's); (ii) activated expression in tumor cells; and (iii) transforming activity in cultured mouse cells. we have been exploring the hypothesis that retroviruses lacking oncogenes activate cellular oncogenes by insertional mutagenesis. our approach is to locate proviruses within the chromosomal dna of clonal populations of tumor cells, and to identi ... | 1983 | 6867028 |
| immunohistochemical identification of group specific antigen in avian leukosis virus infected chickens. | an indirect immunoperoxidase method was employed in the detection of the group specific antigen of avian leukosis virus in the oviduct, spleen, myocardium and bursae of fabricius of chickens. in the magnum of the oviduct the group specific antigen was detected at the base and in the lumina of glands. in the spleen the group specific antigen was found in and around the arterioles, sheathed capillaries, and in the capsular tissue. in the myocardium the group specific antigen was present in the int ... | 1984 | 6206933 |
| nucleotide sequence 5' of the chicken c-myc coding region: localization of a noncoding exon that is absent from myc transcripts in most avian leukosis virus-induced lymphomas. | we have determined the nucleotide sequence of the 2.2-kilobase-pair region upstream of the chicken c-myc coding exons. using rna blot analysis, we have localized a noncoding exon to a region that is separated from the c-myc coding sequences by an intron of 700-800 base pairs. in most avian leukosis virus-induced lymphomas proviral integration has occurred within, or downstream of, the first exon, thus presumably displacing the regulatory sequences that normally control c-myc expression. more tha ... | 1984 | 6087343 |
| metabolism and expression of rna polymerase ii transcripts in influenza virus-infected cells. | influenza virus infection has adverse effects on the metabolism of two representative rna polymerase ii transcripts in chicken embryo fibroblasts, those coding for beta-actin and for avian leukosis virus (alv) proteins. proviral alv dna was integrated into host cell dna by prior infection with alv. within 1 h after influenza virus infection, the rate of transcription of beta-actin and alv sequences decreased 40 to 60%, as determined by labeling the cells for 5 min with [3h]uridine and by in vitr ... | 1984 | 6095046 |
| influence of endogenous viral (ev) gene expression and strain of exogenous avian leukosis virus (alv) on mortality and alv infection and shedding in chickens. | two experiments were conducted to determine the influence of endogenous viral (ev) gene expression on the response of chicken to day-old inoculation with two laboratory and two field strains of avian leukosis virus (alv). the ev2- and ev3-negative semi-congenic chickens had much higher mortality from a unique non-neoplastic syndrome (nns) than ev2- and ev3-positive semi-congenic chickens after inoculation with alv strain rav-1. the three other alv strains induced little nns. all four strains of ... | 1984 | 6098248 |
| proviral deletions and oncogene base-substitutions in insertionally mutagenized c-myc alleles may contribute to the progression of avian bursal tumors. | bursal lymphomas induced in chickens by avian leukosis viruses (alvs) harbor proviral insertions that augment expression of an adjacent cellular oncogene, c-myc. to analyze such insertionally mutagenized c-myc genes in greater detail, we isolated molecular clones from two independent tumors. precise proviral integration has occurred within the transcribed region of the c-myc gene in both mutant alleles. the proviruses bear different internal deletions that preclude the expression of the gag, pol ... | 1984 | 6322173 |
| specificity of avian leukosis virus-induced hyperlipidemia. | rous-associated virus 7 (rav-7) is a subgroup c avian leukosis virus which does not transform cells in vitro or carry an oncogene. when injected into 1-day-old hatched chicks, rav-7 causes a low incidence of lymphoid leukosis after a latent period of several months. in contrast, infection of 10-day-old chicken embryos with rav-7 leads to a disease syndrome characterized by stunting, obesity, atrophy of the bursa and the thymus, high triglyceride and cholesterol levels, reduced thyroxine levels, ... | 1984 | 6323732 |
| isolation of a feline leukaemia provirus containing the oncogene myc from a feline lymphosarcoma. | the molecular mechanism by which feline leukaemia virus (felv) induces lymphoid malignancy in domestic cats is largely unknown. using the insertional activation model of c-myc by avian leukosis virus in the induction of bursal lymphoma in chickens, we have now characterized the c-myc locus in feline tissues and investigated the possibility that felv may also insert within feline c-myc. we used the 1.5 kilobase (kb) psti fragment of mc29 v-myc in southern blot analysis to characterize the structu ... | 1984 | 6325921 |
| avian leukosis virus infection: analysis of viremia and dna integration in susceptible and resistant chicken lines. | avian leukosis viruses induce lymphoid leukosis, a lymphoma which develops within the bursa of fabricius several months after virus infection. chickens from the hyline sc and fp lines are, respectively, susceptible and resistant to avian leukosis virus-induced lymphoid leukosis. we examined plasma and cellular dna obtained from avian leukosis virus-infected chickens for the presence of viremia and integrated viral sequences to determine whether the extent of virus infection is comparable in indi ... | 1984 | 6328031 |
| differential response to avian leukosis virus infection exhibited by two chicken lines. | infection of susceptible chickens with avian leukosis virus (alv) results in the development of bursal lymphomas. these neoplasms develop within the bursa of fabricius following a latent period of several months. the response exhibited by two previously uncharacterized chicken lines to alv infection has been examined. the two lines, hyline sc and fp, responded differently to alv infection. during a 24-week period following intravenous alv infection, 27 of 50 sc chickens developed bursal lymphoma ... | 1984 | 6328748 |
| new findings on the congenital transmission of avian leukosis viruses. | rav-0, an endogenous avian leukosis virus, does not undergo congenital transmission in infected k28 chickens. in contrast, avian leukosis viruses of exogenous origin undergo highly efficient congenital transmission. the relative abilities of endogenous and exogenous viruses to undergo congenital transmission appear to be determined by the p27 capsid proteins of these viruses. | 1984 | 6330893 |
| transcriptional interference in avian retroviruses--implications for the promoter insertion model of leukaemogenesis. | the downstream (3') long terminal repeat (ltr) of an avian retroviral provirus is unable to act as an efficient promoter of transcription when a transcriptionally active upstream (5') ltr is present. this transcriptional interference may explain the observation that only deleted proviruses have been observed inserted adjacent to c-myc in avian leukosis virus induced lymphomas of chickens. | 1984 | 6363938 |
| marek's disease in turkeys: the induction of lesions and the establishment of lymphoid cell lines. | the inoculation of turkeys with large doses of a virulent strain of marek's disease virus (ga strain), but not of two other virulent strains (hprs-16 and jm), was found to induce a disease resembling marek's disease of the chicken. the most prominent lesions were lymphocytic leukaemia and lymphoid and reticular hyperplasia in the spleen and the liver. these developed after a prolonged latent period and the early histological changes (lymphoid cell destruction and reticuloendothelial cell hyperpl ... | 1984 | 18766837 |
| viral aetiology of haemangiosarcoma outbreaks among layer hens. | outbreaks of neoplastic disease defined as haemangiosarcoma occurred among layer flocks of chickens in israel. the disease caused bleeding tumours in the skin and internal organs of young layers, followed by anaemia, cessation of egg production and high mortality up to 20%. avian leukosis virus was isolated from tumour cells which contain several viral dna copies integrated in the cell genome. the isolated virus induced haemangiosarcomas in more than 30% of birds inoculated on the day of hatchin ... | 1984 | 18766881 |
| avian leukosis virus-induced osteopetrosis is associated with the persistent synthesis of viral dna. | dnas from 19 cases of avian leukosis virus-induced osteopetrosis have been analyzed for viral sequences. among these were instances of rapid, intermediate, and slow onset osteopetrosis. the dnas from osteopetrotic bone contained no evidence for osteopetrosis being caused by proviral insertions into or viral transductions of a host protooncogene. instead, dnas from osteopetrotic bone displayed evidence for osteopetrosis being associated with the persistent synthesis of viral dna. each of the 19 d ... | 1985 | 2579505 |
| activation of c-erbb in avian leukosis virus-induced erythroblastosis leads to the expression of a truncated egf receptor kinase. | chicken erythroblastosis caused by avian leukosis virus (alv) is thought to be mediated by activation of the c-erbb/egf receptor oncogene by a promoter-insertion mechanism. here we study the proteins expressed by two alv-induced leukemias and compare them with the avian egf receptor and with the oncogene product of avian erythroblastosis virus (v-erbb) which was shown to be a truncated egf receptor. it appears that the two leukemias express truncated egf receptors of slightly different sizes wit ... | 1985 | 3004938 |
| an enzyme-linked immunosorbent assay for detection of antibodies to exogenous avian leukosis virus. | a microplate enzyme-linked immunosorbent assay (elisa) for detecting antibodies to avian leukosis virus (alv) of subgroups a and b in infected chickens was developed with the use of rous-associated virus (rav)-1 (subgroup a) and rav-2 (subgroup b) antigens purified by sucrose-gradient centrifugation. the antigen was used for elisa after treatment with triton x-100. in the elisa, the subgroup viral antigen reacted strongly with homologous antiserum but also reacted with heterologous antiserum. te ... | 1985 | 3008696 |
| augmented expression of normal c-myc is sufficient for cotransformation of rat embryo cells with a mutant ras gene. | we studied the effect of altered c-myc structure and expression upon the ability of c-myc to promote the transformation of normal rat embryo cells when it was supplemented by ejras (the mutant c-h-ras1 gene from ej/t24 bladder carcinoma cells). we tested several c-myc alleles cloned from normal and tumor tissues of chicken and human origin and found that only ll4myc (derived from a bursal lymphoma in which an avian leukosis virus long terminal repeat resides within the first c-myc intron in the ... | 1985 | 3837844 |
| transcription of three c-myc exons is enhanced in chicken bursal lymphoma cell lines. | the chicken c-myc gene, as defined by its homology to the v-myc gene of mc29 virus, is comprised of two exons. using the techniques of runoff transcription, primer extension, and s1 nuclease protection, we demonstrate that there is a third c-myc exon of approximately equal to 345 base pairs (bp) located 0.7 kbp upstream of the 5' end of the v-myc homology. this first exon is transcribed and present in myc mrna in normal chicken cells. we also examined rna from five cell lines derived from avian ... | 1985 | 3855549 |
| field trials to test the efficacy of polyvalent marek's disease vaccines in layer and broiler breeder chickens. | as a follow-up to earlier trials to evaluate the efficacy of polyvalent marek's disease (md) vaccines in broilers, four trials were conducted with layer or broiler breeder flocks. chickens caccinated with trivalent (md11/75c plus sb-1 plus hvt) and bivalent (sb-1 plus hvt) vaccines were compared with those vaccinated with turkey herpesvirus (hvt) alone. data from three of the four trials indicated polyvalent vaccines were more efficacious than hvt. however, critical interpretations were confound ... | 1985 | 3912753 |
| formation of a transformed follicle is necessary but not sufficient for development of an avian leukosis virus-induced lymphoma. | avian leukosis virus (alv) infection of susceptible chickens induces bursal lymphomas after a latent period of several months. the clonal development of these b-cell tumors is believed to be a multistep process. histopathological changes, referred to as transformed follicles, occur within the target organ soon after virus infection and may represent a proximal stage of lymphomagenesis. to establish further the significance of this lesion and its relationship to the subsequent development of lymp ... | 1985 | 2982144 |
| effects of chemically or virus-induced immunodepression on response of chickens to avian leukosis virus. | the effects of chemically or virus-induced immunodepression on the infection profile (development of viremia and antibody) and shedding of avian leukosis virus (alv) were studied in progeny chickens of experimental or commercial breeder flocks. chickens were infected with alv subgroup a by contact at hatching and by oral inoculation at 4-5 weeks of age. in the first experiment, chickens were inoculated with a virulent strain of infectious bursal disease virus (ibdv) at 1 day or 6 weeks of age. i ... | 1985 | 2985037 |
| high-frequency transduction of c-erbb in avian leukosis virus-induced erythroblastosis. | twenty-one cases of rous-associated virus type 1-induced erythroblastosis have been analyzed for novel restriction endonuclease fragments of c-erbb. twenty of the erythroleukemias contained novel c-erbb fragments; 10 of these were found to contain a proviral insertion in c-erbb, and 10 were found to have a new transduction of c-erbb. each of the proviral insertions was in the same transcriptional orientation as c-erbb, and most appeared to have retained both long terminal repeats as well as 5' v ... | 1985 | 2985798 |
| responses of chickens lacking or expressing endogenous avian leukosis virus genes to infection with exogenous virus. | line 0 chickens that lack endogenous viral (ev) genes and 15i5 x 7 chickens that carry and express ev genes were inoculated with the avian leukosis virus, rav-1, at 1 day of age or as embryos, and maintained to 70 days of age. comparable uninoculated controls were also kept. most of the day-old inoculated chickens developed antibody by 70 days, but as expected, most of the embryo inoculated chickens remained viremic. major differences in response between the lines were only noted after day-old i ... | 1985 | 2986085 |
| insertional activation of c-myc by reticuloendotheliosis virus in chicken b lymphoma: nonrandom distribution and orientation of the proviruses. | chicken syncytial virus, a member of the reticuloendotheliosis virus family, can induce chicken b lymphomas indistinguishable from those caused by avian leukosis virus. previously, we have demonstrated that the chicken syncytial virus proviruses in these tumors are linked to the proto-oncogene c-myc. we have now determined the arrangement of chicken syncytial virus proviruses in 22 tumors. the results indicate that these proviruses, without exception, are integrated upstream from the second c-my ... | 1985 | 2987538 |
| variation in susceptibility to avian sarcoma viruses and expression of endogenous avian leukosis virus antigens in specific pathogen-free chicken lines. | five lines of chickens maintained as specific pathogen-free flocks in australia were characterized in relation to endogenous antigens and endogenous avian leukosis virus expression. embryos of line n were predominantly of c/e phenotype, uniformly positive for group-specific antigen and chick helper factor (gs+chf+) and 38% expressed endogenous virus at a very low titre. embryos of line m4 were uniformly of c/abe phenotype and were either gs+chf+ or gs-chf+. line w19 embryos segregated for suscep ... | 1985 | 2991436 |
| enhanced transcription of c-myc in bursal lymphoma cells requires continuous protein synthesis. | in several bursal lymphoma cell lines in which c-myc transcription is regulated by avian leukosis virus (alv) long terminal repeat (ltr) sequences, protein synthesis inhibition decreases the transcriptional activity of c-myc as well as other ltr driven viral genes. this decrease in transcription is associated with a change in the chromatin structure of c-myc, as measured by deoxyribonuclease i (dnase i) hypersensitivity, and a shift of transcription from the ltr to the normal c-myc promoter. in ... | 1985 | 2999973 |
| patterns of proviral insertion and deletion in avian leukosis virus-induced lymphomas. | sixty-eight lymphomas induced by eight different avian leukosis viruses have been analyzed on southern blots for virus-induced mutations in the chicken c-myc gene. sixty-six of the lymphomas exhibited a proviral insertion in c-myc, whereas one exhibited a new transduction of c-myc. sixty-four of the proviral insertions were in the same transcriptional orientation as c-myc. two were in the opposite transcriptional orientation. all of the insertions were upstream of the protein-coding sequences of ... | 1986 | 3001351 |
| gene insertion into the chicken germ line by retroviruses. | we injected chick syncytial strain of reticuloendotheliosis virus (cs-rev) and wild type and recombinant avian leukosis virus (alv) near the blastoderm of unincubated fertilized embryos and cs-rev intra-abdominally at day of hatch, and we progeny tested the surviving alv viremic males and rev viremic males and females for transmitted viral genetic material. a number of positive progeny were identified and their deoxyribonucleic acid (dna) analyzed for restriction enzyme fragments that hybridized ... | 1986 | 3035526 |
| unique sequence, ski, in sloan-kettering avian retroviruses with properties of a new cell-derived oncogene. | the sloan-kettering viruses (skvs) are a group of transforming retroviruses that were isolated from chicken embryo cells which had been infected with the avian leukosis virus transformation-defective bratislava 77 (tdb77). each of the skv isolates was shown to contain multiple genomes of different sizes indicating the presence of several viruses in addition to tdb77. to identify and characterize the putative transforming gene(s) of the skvs, we used hybridization selection to isolate the fractio ... | 1986 | 3754014 |
| absence of influence on immune competence by the sex-linked gene (k) determining slow feathering in white leghorn chickens. | males of white leghorn strain crosses heterozygous (kk) for the sex-linked feathering locus genes were mated to rapid-feathering (k-) females to produce rapid- and slow-feathering chicks of both sexes. k did not influence humoral-mediated immunity against challenge with sheep erythrocytes, killed brucella abortus, or killed infectious bursal disease virus. chicks challenged at 3 weeks of age had higher primary responses and higher titers of 2-mercaptoethanol-resistant antibody (igg) than those c ... | 1986 | 3814012 |
| susceptibility of avian b lymphocytes to retroviral infection parallels that of fibroblasts. | the ability of conventional virus receptors to mediate infection and transformation of immature b cells by the avian leukosis virus (alv) was analyzed in chimeric chickens whose bursa of fabricius contained a mixture of b cells from subgroup a virus receptor-positive and -negative chickens. the data indicate that factors that determine resistance of fibroblasts to alv infection also apply to bursal cells and that other receptors expressed by b cells, i.e., antigen or mitogen receptors, do not in ... | 1986 | 3012871 |
| resistance of line 6(3) chickens to reticuloendotheliosis-virus-induced bursa-associated lymphomas. | chickens of lines 6(3) and 151(5) x 7(1) were inoculated with the chick syncytial strain of reticuloendotheliosis virus (rev) or with the rous-associated virus-i of avian leukosis virus (alv) at hatching. at 4, 10, 16, and 36 weeks post inoculation (pi), chickens were tested for rev- and alv-induced viremia and antibody. the incidence of rev- or alv-induced bursa-associated lymphomas in line 6(3) chickens was compared with that in line 151(5) x 7(1) chickens. inoculation of rev at hatching resul ... | 1986 | 3013782 |
| characterization of monoclonal antibodies to avian leukosis viruses. | hybridoma cell lines secreting monoclonal antibody (mca) to avian leukosis virus (alv) structural proteins p27 and p19 have been established. in an indirect enzyme-linked immunosorbent assay (elisa), mca 6al20 (igg1 isotype) reacted with rpl-40 (alv subgroup a), avian myeloblastosis virus (amv) (a mixture of subgroups a and b), rous-associated virus (rav)-2 (subgroup b), and carr-zilber strain of rous sarcoma virus (cz-rsv) (subgroup d) but not with prague strain of rsv (prc-rsv) (subgroup c) or ... | 1986 | 3015099 |
| replication-competent endogenous avian leukosis virus in commercial lines of meat chickens. | group-specific (gs)-antigen-positive egg albumen in seven commercial lines of meat chickens was found to result from the presence of endogenous avian leukosis virus (alv); these lines had resisted selection attempts to reduce the shedding rate. in two meat lines, exogenous as well as endogenous alv contributed to the gs-antigen shedding. all hens that produced gs-antigen-positive albumen transmitted endogenous alv to a high proportion of their embryos (20 to 100%). hens shedding gs-antigen to al ... | 1986 | 3015111 |
| characterization of rous sarcoma virus-related sequences in the japanese quail. | we detected sequences related to the avian retrovirus rous sarcoma virus within the genome of the japanese quail, a species previously considered to be free of endogenous avian leukosis virus elements. using low-stringency conditions of hybridization, we screened a quail genomic library for clones containing retrovirus-related information. of five clones so selected, one, lambda q48, contained sequence information related to the gag, pol, and env genes of rous sarcoma virus arranged in a contigu ... | 1986 | 3016302 |
| transmission of (ltr, v-src, ltr) without recombination with a helper virus. | we have analyzed transmission of (ltr, v-src, ltr) cryptic structure integrated in the h-19 mammalian tumor cell line. from this cell line different isolates of transforming virus were rescued in heterokaryons produced by fusion with chicken fibroblasts infected by replication-competent avian leukosis virus rav-1. one of them (f6) was used for the transformation of avian cells in the absence of the helper virus. in four transformed cell lines studied, the (ltr, v-src, ltr) structure was again in ... | 1986 | 3016994 |
| immune response to avian leukosis virus determined by the cell-mediated focus-reduction (cemfor) assay. | a cell-mediated focus-reduction (cemfor) assay was used to determine the sequential development of cell-mediated immunity to avian oncornaviruses and the nature of the cells participating in this immune reaction. peripheral blood leukocytes of leghorn chickens that had regressed rous sarcoma virus-induced tumors or were immune to avian leukosis virus had cemfor activity. the response was biphasic early in the infection. peripheral blood leukocytes from nonimmune chickens or viremic, immunologica ... | 1986 | 3018344 |
| selective integration of avian leukosis virus in different hematopoietic tissues. | hematopoietic tissues obtained from avian leukosis virus (alv)-infected hyline sc chickens were analyzed for the presence of integrated viral dna sequences. cells were prepared from bone marrow, bursa, spleen, thymus, and peripheral blood. following the removal of erythrocytes, cellular dnas from each of these tissues were examined by southern analysis. during the first few weeks of infection, dna from the bone marrow contained as many as 0.5 copies of viral dna per haploid genome. cells from th ... | 1986 | 3024400 |
| restrictions that influence avian leukosis virus-induced lymphoid leukosis. | 1986 | 3024914 | |
| the cellular homologue of the transforming gene of skv avian retrovirus maps to human chromosome region 1q22----q24. | we report the chromosomal localization of the cellular oncogene ski, the putative oncogene of the sloan-kettering viruses (skvs), a group of transforming retroviruses that had been isolated from chicken embryo cells infected with the avian leukosis virus tdb77. southern blot analysis of dna from mouse x human somatic cell hybrids with the v-ski probe established synteny with chromosome 1, but excluding the region 1pter----q21. in situ hybridization of the same probe both to human spermatocyte pa ... | 1986 | 3026737 |
| features of the chicken c-myc gene that influence the structure of c-myc rna in normal cells and bursal lymphomas. | the chicken c-myc gene is the target for proviral insertion mutations in bursal lymphomas and has been transduced to generate several viral oncogenes, but the boundaries of its exons have not been securely established. to define the landmarks of the chicken c-myc gene necessary to produce its mrna, we used an rnase protection assay and a cdna clone to analyze the c-myc mrnas from normal chicken embryos and from two bursal lymphomas: ll6, which contains an avian leukosis virus provirus downstream ... | 1986 | 2431293 |
| endogenous viral genes in a slow-feathering line of white leghorn chickens. | endogenous viruses related to avian leukosis viruses were characterised in three sire families of slow-feathering white leghorns. progeny released infectious endogenous virus when extracts were tested on subgroup e susceptible fibroblasts. restriction fragment length polymorphisms (rflps) indicated germline transmission of ev1, ev5, ev21 and a hitherto unreported locus ev22 among three sire families. the association of ev21 with the release of infectious endogenous virus precluded phenotypic cha ... | 1986 | 18766541 |
| feather pulp organ cultures for assessing host resistance to infection with avian leukosis-sarcoma viruses. | the purpose of this study was to improve in vitro procedures for detecting cellular resistance to the avian leukosis-sarcoma group of viruses. four feather pulp organ cultures (fpoc) were prepared from each chicken by placing pulp squeezed from feathers in wells of microtitre plates that contained culture medium. two of the four fpoc were inoculated with rous sarcoma virus (rsv) of subgroup a and 5 to 6 days later the fluids from all four cultures were assayed for virus by inoculating chicken em ... | 1987 | 18766632 |
| variation in tolerance induction and oncogenicity due to strain of avian leukosis virus. | chickens were inoculated as embryos or orally at hatching with various doses of four strains of avian leukosis virus (alv) subgroup a (rav-1, rpl40, rpl41 and rpl42). viraemia, antibody and tumours in chickens of various groups were compared; alv shedding was determined, but only in chickens inoculated with virus at hatching. results indicate that 95% to 100% of chickens embryonally inoculated with 105 infectious units of virus were viraemic at hatching, regardless of the strain of virus used. h ... | 1987 | 18766653 |
| 3'-azido-3'-deoxythymidine inhibits the replication of avian leukosis virus. | we tested the ability of the thymidine analog 3'-azido-3'-deoxythymidine (bwa509u) to inhibit the replication of the retrovirus avian leukosis virus. inhibition was measured with two different assays: inhibition of a single round of virus replication and inhibition of virus spread through a cell culture. with both assays, we detected inhibition of virus growth, although inhibition of a single round of virus replication required a 40-fold higher drug concentration than did inhibition of virus spr ... | 1987 | 2441079 |
| embryonic infection with the endogenous avian leukosis virus rous-associated virus-0 alters responses to exogenous avian leukosis virus infection. | we inoculated susceptible chicken embryos with the endogenous avian leukosis virus rous-associated virus-0 (rav-0) on day 6 of incubation. at 1 week after hatching, rav-0-infected and control chickens were inoculated with either rav-1 or rav-2, exogenous viruses belonging to subgroups a and b, respectively. the chickens injected with rav-0 as embryos remained viremic with exogenous virus longer and either failed to develop type-specific humoral immunity to exogenous virus or developed it later t ... | 1987 | 3027399 |
| genetic determinants of neoplastic diseases induced by a subgroup f avian leukosis virus. | two subgroup f avian leukosis viruses, ring-necked pheasant virus (rpv) and rav-61, were previously shown to induce a high incidence of a fatal proliferative disorder in the lungs of infected chickens. these lung lesions, termed angiosarcomas, appear rapidly (4 to 5 weeks after infection), show no evidence of proto-oncogene activation by proviral integration, and are not induced by avian leukosis viruses belonging to other subgroups. to identify the viral sequences responsible for induction of t ... | 1987 | 3029416 |
| an aberrant avian leukosis virus provirus inserted downstream from the chicken c-myc coding sequence in a bursal lymphoma results from intrachromosomal recombination between two proviruses and deletion of cellular dna. | a chicken bursal lymphoma, ll6, contains avian leukosis virus dna integrated 3' of the c-myc coding sequences, unlike all other examined bursal lymphomas, which have integrations 5' to c-myc. to better understand this unusual mutation, we examined a molecular clone containing the ll6 c-myc gene and determined the structure of the proviral insertion by dna sequencing. viral dna begins 575 base pairs downstream of the c-myc coding sequences within the untranslated region, disrupting the use of the ... | 1987 | 3033315 |
| [the genome of chickens free of endogenous avian leukosis-sarcoma proviruses contains sequences distantly related to rous sarcoma virus]. | line of brown leghorn chickens free of rav-o-type endogenous proviruses was obtained by selection under blot hybridization control. a set of dispersed sequences distantly related to avian leukosis virus genome was found in dna of these chickens by means of hybridization in non-stringent conditions. different restriction fragments were detected by gag, pol and env hybridization probes. | 1987 | 3033485 |
| cultivation of avian rotaviruses in chicken lymphocytes and lymphoblastoid cell lines. | avian rotavirus isolates were used to infect normal chicken spleen cells, lymphoblastoid t cell lines transformed by marek's disease virus, an avian leukosis virus-transformed b cell line, and a reticuloendotheliosis virus-transformed line, which is a pre-b, pre-t cell line. all five isolates tested were able to infect spleen cells and the three types of lymphoblastoid cell lines, suggesting that avian rotaviruses can infect both b and t cells. splenic lymphocytes were considerably less suscepti ... | 1987 | 3034208 |
| b-lymphoma induction by reticuloendotheliosis virus: characterization of a mutated chicken syncytial virus provirus involved in c-myc activation. | nondefective reticuloendotheliosis virus induces chicken bursal lymphoma in a manner similar to that of avian leukosis virus. the provirus integrates in the c-myc locus and uses a promoter insertion mechanism to activate c-myc expression. we cloned a provirus involved in c-myc activation from a b lymphoma. detailed structural characterization of this clone, including sequence determination, revealed proviral insertion at 512 base pairs preceding the second c-myc exon. the provirus has a deletion ... | 1987 | 3035210 |
| an avian transforming retrovirus isolated from a nephroblastoma that carries the fos gene as the oncogene. | a new avian transforming retrovirus, nk24, was isolated from a chicken with a nephroblastoma. this transforming virus induced fibrosarcomas with osteogenic cell proliferation and nephroblastomas in vivo and transformed fibroblast cells in vitro. from extracts of nk24-transformed cells, anti-gag serum immunoprecipitated a 100-kilodalton nonglycosylated protein with no detectable protein kinase activity. an nk24 provirus present in infected quail cells was molecularly cloned and subjected to nucle ... | 1987 | 2824811 |
| reduced expression of mhc class i antigens in chicken fibroblasts transformed by rous sarcoma virus. | monoclonal monomorphic as well as polyclonal antibodies against h-b class i (b-f) antigen were used to evaluate the expression of these molecules on normal and rsv-transformed chick embryo fibroblasts. the results indicate that chicken fibroblasts transformed in vitro by the schmidt-ruppin strain rous sarcoma virus of subgroup b (sr-rsv-b) present reduced h-b class i antigen expression as compared to uninfected cells of the same inbred strain. this quantitative reduction was observed at the cell ... | 1987 | 2826262 |
| 5' long terminal repeats of myc-associated proviruses appear structurally intact but are functionally impaired in tumors induced by avian leukosis viruses. | b-cell lymphomas induced in chickens infected with avian leukosis viruses are characterized by integration of the virus within the cellular myc locus and alteration of c-myc expression. although avian leukosis viruses are intact, replication-competent retroviruses, the structures of many myc-associated proviruses are altered by deletions, raising the possibility that proviral defectiveness plays an essential role in oncogenesis. we found that all myc-associated proviruses in 21 independent tumor ... | 1987 | 3037111 |
| targeting of chemical mutagens to differentiating b-lymphocytes in vivo: detection by direct dna labeling and sister chromatid exchange induction. | in vivo systems for analyzing mutagen interactions with a specific differentiating cell population are rare. taking advantage of the unique anatomical features of the bursa of fabricius in the chicken, we explored the possibility of targeting chemical mutagens to a defined differentiating cell population in the animal, namely, the b-lymphocytes series. such cells are known to be the targets for the oncogene-activating avian leukosis virus. targeting of chemicals to cells of the bursa was demonst ... | 1987 | 3492371 |
| development of avian sarcoma and leukosis virus-based vector-packaging cell lines. | we have constructed an avian leukosis virus derivative with a 5' deletion extending from within the trna primer binding site to a saci site in the leader region. our aim was to remove cis-acting replicative and/or encapsidation sequences and to use this derivative, rav-1 psi-, to develop vector-packaging cell lines. we show that rav-1 psi- can be stably expressed in the quail cell line qt6 and chicken embryo fibroblasts and that it is completely replication deficient in both cell types. moreover ... | 1988 | 2828649 |
| rapid induction of b-cell lymphomas: insertional activation of c-myb by avian leukosis virus. | eu-8 is a recombinant avian leukosis virus (alv) constructed in vitro, which carries long terminal repeats and gag and pol genes from ring-necked pheasant virus and the env gene from ur2av. unlike either parent virus, when injected into 10-day-old chicken embryos, eu-8 induces a high incidence of clonally arising b-cell lymphomas within an unusually short latent period, often causing death within 5 to 7 weeks after infection. these tumors differ from the classic lymphoid leukosis induced by alv ... | 1988 | 2831403 |
| isolation of a variant endogenous avian leukosis virus: non-productive exogenous infection with endogenous viruses containing p27 and p27(0). | ten replication-competent endogenous avian leukosis viruses (alvs) with subgroup e specificity were isolated from six commercial chicken lines of mixed breed. all the alvs isolated belonged to a variant class of endogenous viruses with a major group-specific antigen, p27, identical in size to that of exogenous viruses and different from the p27 degrees of endogenous viruses isolated from white leghorn chickens. it was possible to infect chickens exogenously with endogenous viruses (containing p2 ... | 1988 | 2832527 |
| proviral-activated c-erbb is leukemogenic but not sarcomagenic: characterization of a replication-competent retrovirus containing the activated c-erbb. | avian leukosis virus (alv) induces erythroblastosis in chickens by integrating its dna into the host c-erbb locus and by activating expression of truncated c-erbb transcripts. although there is a 100% correlation of c-erbb activation with alv-induced erythroblastosis, direct evidence that the activated c-erbb is oncogenic has not been established. we have constructed a replication-competent retrovirus containing the activated c-erbb to investigate its transforming potential. the rous c-erbb viru ... | 1988 | 2833627 |
| avian leukosis virus (alv) infection, shedding, and tumors in maternal alv antibody-positive and -negative chickens exposed to virus at hatching. | chickens highly susceptible to avian leukosis virus (alv) infection and tumors, with and without alv subgroup a maternal antibody (mab), were infected with a field strain of alv subgroup a at hatching. viremia, antibody development, cloacal and albumen shedding, and tumors in chickens with mab (mab+) were compared with those in chickens lacking mab (mab-). at 18 weeks of age, the incidence of viremia was significantly lower in mab+ chickens than in mab- chickens; further, mab significantly reduc ... | 1988 | 2838017 |
| immune response of chickens inoculated with a recombinant avian leukosis virus. | specific-pathogen-free embryos (18-day incubation) and hatched chicks were inoculated with a recombinant avian leukosis virus (alv) produced by recombinant dna techniques. enzyme-linked immunosorbent assays were used to measure the production of viral-protein-specific antibody and the viral protein, p27, in the serum at 2, 5, 8, 14, and 20 weeks of age. of the inoculated chickens surviving to 20 weeks, 64% produced viral-protein-specific antibodies and 42% transiently produced the viral protein, ... | 1988 | 2838018 |
| lability of leukosis virus enhancer-binding proteins in avian hematopoeitic cells. | bursal lymphomas induced by avian leukosis virus (alv) are characterized by integration of long terminal repeat (ltr) enhancer sequences next to the myc proto-oncogene and by subsequent myc hyperexpression. nuclear runoff transcription analyses have shown that protein synthesis inhibition specifically decreases transcription of ltr-enhanced genes in bursal lymphoma cell lines (m. linial, n. gunderson, and m. groudine, science 230:1126-1132, 1985). here, we show that ltr-enhanced transcription is ... | 1988 | 2839698 |
| ev 22, a new endogenous avian leukosis virus locus found in chickens with spontaneous autoimmune thyroiditis. | chickens of the obese strain (os) develop a hereditary spontaneous autoimmune thyroiditis (sat) which closely resembles human hashimoto's disease. analysis of the endogenous viruses harboured by these animals revealed a new endogenous virus (ev22) detected as a 5.5 kb sac i fragment. crossbreeding experiments showed that ev22 is vertically transmitted as an autosomal trait not associated with major histocompatibility (mhc) alleles. preliminary experiments indicate that ev22 does not necessarily ... | 1988 | 2840875 |
| resistance of chickens to rous sarcoma virus challenge following immunization with a recombinant avian leukosis virus. | an attenuated recombinant avian leukosis virus (alv) produced by recombinant dna techniques was examined for its ability to provide resistance to rous sarcoma virus (rsv) challenge. specific-pathogen-free chicken embryos (18-day incubation) and hatched chicks inoculated with recombinant alv produced significantly smaller tumors than sham-inoculated controls upon challenge with rsv 2 weeks postinoculation; inoculation with rav-1 produced similar results. specific-pathogen-free hens inoculated wit ... | 1988 | 2848482 |
| influence of congenital transmission of endogenous virus-21 on the immune response to avian leukosis virus infection and the incidence of tumors in chickens. | after contact exposure to strain rpl-40 avian leukosis virus-infected hatchmates, a dilatory neutralizing antibody response and prolonged rpl-40 viremia was found among most pullets that were congenitally infected with endogenous virus 21 (ev21). conversely, most of the hatchmates that were not congenitally infected seroconverted within 10 wk after exposure to strain rpl-40 virus. compared with noncongenitally infected hatchmates, ev-21 infection-induced tolerance to pathogenic avian leukosis vi ... | 1988 | 2853868 |
| mechanism of c-erbb transduction: newly released transducing viruses retain poly(a) tracts of erbb transcripts and encode c-terminally intact erbb proteins. | we have previously shown that avian leukosis virus (alv) induces erythroblastosis by insertional activation of the c-erbb gene. in 25% of the alv-induced leukemic samples we have analyzed, acute retroviruses that have captured the activated erbb oncogene were released. the unusually high frequency at which erbb transduction occurs makes this an ideal system for studying the mechanism of oncogene transduction. in addition, these leukemic samples provide a rich source for the isolation of novel er ... | 1988 | 2897475 |
| the v-ski oncogene encodes a truncated set of c-ski coding exons with limited sequence and structural relatedness to v-myc. | the nucleotide sequence of a biologically active v-ski gene from a cloned proviral segment shows that ski is a 1,312-base sequence embedded in the p19 region of the avian leukosis virus gag gene. the v-ski sequence contains a single open translational reading frame that encodes a polypeptide with a molecular mass of 49,000 daltons. the predicted amino acid sequence includes nuclear localization motifs that have been identified in other nuclear oncoproteins. it also contains a proline-rich region ... | 1989 | 2674685 |
| isolation and characterization of three distinct cdnas for the chicken c-ski gene. | three types of c-ski cdnas have been isolated from two different chicken cdna libraries. sequence comparisons suggest that the cdnas derive from alternatively spliced mrnas. a short stretch of sequence homology that exists between c-ski and avian leukosis virus may have played a role in viral transduction. | 1989 | 2779576 |
| major histocompatibility complex class ii (ia-like) antigens on chicken embryo fibroblasts: effect of transformation by rous sarcoma virus. | in this study, three monomorphic monoclonal antibodies to chicken mhc class ii molecules (b-l) were tested for reactivity in normal and rsv-transformed embryo fibroblasts. the immunocytochemical staining, the cell-bound elisa assay, and the immunoprecipitation analysis showed that all three antibodies reacted with the b-l (ia-like) molecules on normal cells of different genotypes. conversely, the expression of these antigens was not detected in fibroblasts cultured from feather follicles of adul ... | 1989 | 2483835 |
| augmentation of retrovirus-induced lymphoid leukosis by marek's disease herpesviruses in white leghorn chickens. | our objective was to determine whether the cell-associated herpesvirus vaccines used in chickens to control marek's disease tumors can augment development of lymphoid leukosis (ll) induced by exogenous avian leukosis virus (alv). various single or mixed marek's disease vaccines were inoculated at day 1, and alv was injected at 1 to 10 days, with chickens of several experimental or commercial strains. development of ll was monitored at 16 to 48 weeks in various experiments. in several strains of ... | 1989 | 2536088 |