title: Strain-dependent expression of endogenous mouse-tropic leukemia viruses in chemically induced murine leukemias.
abstract: The effects of two chemical carcinogens, nitrosobutylurea and 7,12-dimethylbenz-(a) anthracene, on the expression of endogenous N- and B-tropic viruses were studied. The mice used were from two inbred strains, C57BL/6 and DDD-Fvr, and from 13 partially inbred strains derived from the cross of C57BL/6 with DDD-Ffr. These mouse strains are classified into three groups by the pattern of expression of endogenous viruses in normal, aged mice: (1) negative for both viruses; (2) positive for N-tropic virus only; and (3) positive for both viruses. Mice were given the carcinogens, and were tested at various intervals by the UV-XC procedure for the viruses in the spleens and other enlarged organs. Irrespective of the presence or absence of leukemias, the carcinogen-treated mice showed the same pattern of expression of endogenous viruses as that of non-treated normal mice. It can be concluded that the activation of the endogenous viruses is dependent on the mouse strains and that the growth of the activated viruses is not a necessary step for the chemical induction of leukemias.
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene; D000367:Age Factors; D000818:Animals; D001551:Benz(a)Anthracenes; D009052:Leukemia Virus, Murine / Q000187:drug effects* / Q000302:isolation & purification; D007942:Leukemia, Experimental / Q000139:chemically induced* / Q000382:microbiology; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D009607:Nitrosourea Compounds; D013045:Species Specificity; D013154:Spleen / Q000382:microbiology; D013268:Stimulation, Chemical; D014779:Virus Replication / Q000187:drug effects*
chemical_list: D001551:Benz(a)Anthracenes; D009607:Nitrosourea Compounds; D015127:9,10-Dimethyl-1,2-benzanthracene