title: Genetic transmission of endogenous N- and B-tropic murine leukemia viruses in low-leukemic strain C57BL/6.
abstract: Spontaneous expression of endogenous N- and B-tropic murine leukemia viruses was stu1bb), DDD (Fuv-1nn), DDD-Fvr (fv-1nn), (DDD or DDD-Fvr times C57BL/6)F1, and 16 partially inbredlines with either the Fv-1nn or Fv-1bb genotype, which had been established from hybrids between C57BL/6 and DDD-Fvr. When tested at middle age, virus-positive mice were found in C57BL/6, F1 hybrids, and 9 out of 16 partially inbred lines. N-tropic viruses were isolated from Fv-1nn, Fv-1bb mice, whereas B-tropic viruses, except for one isolate, were from Fv-1bb mice only. C57BL/6 mice were positive for both N- and B-tropic viruses, whereas DDD-Fvr mice were negative. With respect to the Fv-1 genotype and the presence of endogenous murine leukemia viruses, the partially inbred lines were grouped into five types: (i) Fv-1bb, both N- and B-tropic virus positive, like C57BL/6; (ii) Fv-1nn, virus negative, like DDD-Fvr; (iii) Fv-1bb, virus negative; (iv) Fv-1nn, only N-tropic virus positive; and (v) less convincingly, Fv-1bb, only B-tropic virus positive. These findings indicate that the transmission of N- and B-tropic viruses in C57BL/6 is genetically controlled and that the expression of B-tropic virus, but not of N-tropic virus, is closely associated with the Fv-1 genotype.
mesh_terms: D000367:Age Factors; D000818:Animals; D005796:Genes; D005838:Genotype; D006824:Hybridization, Genetic; D009052:Leukemia Virus, Murine / Q000302:isolation & purification*; D051379:Mice; D008806:Mice, Inbred AKR / Q000382:microbiology; D008807:Mice, Inbred BALB C / Q000382:microbiology; D008810:Mice, Inbred C57BL / Q000382:microbiology*; D008815:Mice, Inbred Strains / Q000382:microbiology; D008954:Models, Biological; D013045:Species Specificity; D013154:Spleen / Q000382:microbiology; D010948:Viral Plaque Assay