title: Mechanisms of oncogenesis by subgroup F avian leukosis viruses.
abstract: Subgroup F avian leukosis viruses, such as RAV-61 and ring-necked pheasant virus, are recombinants between exogenous chicken retroviruses and endogenous pheasant viruses and contain new envelope (env) genes. Chickens infected as 10-day-old embryos with subgroup F viruses develop fibrosarcomas, nephroblastomas, osteopetrosis, B-cell lymphomas, and a high incidence of a proliferative disorder involving the lung. Fibrosarcomas, nephroblastomas, and lymphomas appear after long latent periods (3 to 12 months). They contain discrete virus-cell junction fragments and are therefore clonal outgrowths of a single infected cell. Two ring-necked pheasant virus-induced B-cell lymphomas and an adenocarcinoma of the abdomen contained proviruses integrated at the c-myc locus and elevated levels of myc mRNA. At least four of the fibrosarcomas appeared to contain proviruses integrated at a common site, suggesting that a specific cellular gene may be involved in these tumors. The host gene has not been identified, however; 16 different oncogene probes failed to hybridize to fibrosarcoma junction fragments. In contrast to these neoplasms, lung lesions appeared rapidly (4 to 5 weeks), showed no evidence of clonality, and lacked long terminal repeat-initiated transcripts other than viral 35S and 21S mRNA. We conclude, therefore, that subgroup F retroviruses induce the proliferative disorder of the lung by a different mechanism.
mesh_terms: D000818:Animals; D001353:Avian Leukosis / Q000382:microbiology*; D001354:Avian Leukosis Virus / Q000235:genetics* / Q000472:pathogenicity; D001483:Base Sequence; D002471:Cell Transformation, Neoplastic; D002642:Chick Embryo; D002645:Chickens; D004262:DNA Restriction Enzymes; D004279:DNA, Viral / Q000235:genetics; D009693:Nucleic Acid Hybridization; D009857:Oncogenes; D011061:Poly A / Q000235:genetics; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D012333:RNA, Messenger
chemical_list: D004279:DNA, Viral; D012333:RNA, Messenger; D011061:Poly A; D012313:RNA; D004262:DNA Restriction Enzymes