title: Transfer, by selective breeding, of the pathogenic Mtv-2 endogenous provirus from the GR strain to a wild mouse line free of endogenous and exogenous mouse mammary tumor virus.
abstract: The GR laboratory mouse strain has five endogenous proviral copies of the mouse mammary tumor virus (MMTV). One of these, Mtv-2, is unique because it causes mammary carcinomas in virtually 100% of breeding GR females prior to 1 year of age. To facilitate studies of this locus in particular, and mammary tumorigenesis in general, we genetically tailored a new mouse line, WXG-2, which bears Mtv-2 as its only endogenous MMTV provirus. The WXG-2 line was constructed by making hybrids between the GR strain and a wild mouse line free of both endogenous and exogenous MMTV, backcrossing to the MMTV-free line, and fixing the Mtv-2 locus in a population with the desired genotype. Mammary tumors were observed in 5 of the 20 hybrid females carrying the endogenous Mtv-2 provirus. The WXG-2 line represents a new model system for studying MMTV-induced mammary tumorigenesis in the absence of multiple endogenous proviruses.
mesh_terms: D000818:Animals; D003433:Crosses, Genetic; D005260:Female; D005814:Genes, Viral; D005838:Genotype; D008297:Male; D008325:Mammary Neoplasms, Experimental / Q000382:microbiology*; D008324:Mammary Tumor Virus, Mouse / Q000235:genetics*; D051379:Mice / Q000235:genetics / Q000382:microbiology*; D008815:Mice, Inbred Strains