title: Radiation induction of endogenous type C virus from mouse cells transformed in vitro by murine sarcoma virus.
abstract: Cell lines from AKR and BALB/c mouse embryos were compared for their sensitivity to X-ray induction of endogenous type C virus. K-Balb cells, a Balb/3T3 cell line nonproductively transformed by Kirsten murine sarcoma virus, were found to be sensitive to X-irradiation. At a dose as low as 50 R, X-rays induced virus expression in K-Balb cells, and the induction frequency increased with increasing dose of X-rays up to 400 R. Among two classes of inducible endogenous viruses carried by K-Balb cells, only Balb:virus-2 was activated by X-irradiation, whereas both Balb:virus-1 and Balb:virus-2 were activated after the cells were treated with 5-iodo-2'-deoxyuridine. UV light and 4-nitroquinoline 1-oxide were also shown to induce virus expression in K-Balb cells. The virus-induction frequency for these physical and chemical carcinogens was much lower (approximately 3 times 10(-4)) than that for 5-bromo-2'-deoxyuridine (approximately 1 times 10(-1)).
mesh_terms: D015112:4-Nitroquinoline-1-oxide / Q000494:pharmacology; D001973:Bromodeoxyuridine / Q000494:pharmacology; D002471:Cell Transformation, Neoplastic; D002999:Clone Cells / Q000382:microbiology; D004307:Dose-Response Relationship, Radiation; D012190:Retroviridae / Q000528:radiation effects*; D009053:Sarcoma Viruses, Murine; D013997:Time Factors; D014466:Ultraviolet Rays; D014779:Virus Replication / Q000187:drug effects / Q000528:radiation effects*; D014965:X-Rays
chemical_list: D015112:4-Nitroquinoline-1-oxide; D001973:Bromodeoxyuridine