title: Bvr-1, a restriction locus of a type C RNA virus in the feline cellular genome: pleiotropic restriction of endogenous BALB virus in cat X mouse somatic cell hybrids.
abstract: Bvr-1 is a dominant X-linked feline gene which restricts the replication of B-tropic murineleukemia virus (B-MuLV) in somatic cell hybrids between murine BALB/c-RAG cells and FL-74 feline cells. Since the hybrids were originally derived by the hypoxanthine aminopterin thymidine selection scheme, counter selection experiments on 6-thioguanine result in preferential survival of hybrid cells which have spontaneously lost the feline X-chromosome on which is located the structural gene for hypoxanthine guanine phosphoribosyl transferase (IMP: pyrophosphate phosphoribosyl transferase, E.C. 2.4.2.8) and Bvr-1. Back selected Bvr-1- cells express high parental levels of B-MuLV. Bvr-1 effectively restricts the IdU-mediated induction of the endogenous xenotropic BALB virus (BALB: virus 2) but not the endogenous N-tropic virus (BALB: virus 1). Pleiotropic restriction of B-MuLV and X-MuLV, but not N-MuLV suggests that the viral targets of Bvr-1 (either viral components or functions in viral assembly) of the B-tropic and X-tropic endogenous BALB viruses are similar to each other but distinct from the target in the N-tropic virus. Very low levels of B-MuLV are detected in restricted cells, but this residual virus is not infectious in either NIH-3T3 or BALB-3T3 mouse cells which are genotypically Fv-1N/Fv-1N and Fv-1B/Fv-1B, respectively. Passage of residual virus through host cells without Fv-1 related restriction (SC-1) results in production of infectious B-MuLV indistinguishable from that produced by RAG parent cells.
mesh_terms: D000818:Animals; D002415:Cats / Q000235:genetics* / Q000382:microbiology; D002460:Cell Line; D005260:Female; D005796:Genes; D008040:Genetic Linkage; D006822:Hybrid Cells; D009052:Leukemia Virus, Murine / Q000254:growth & development*; D051379:Mice; D008807:Mice, Inbred BALB C / Q000235:genetics / Q000382:microbiology; D014779:Virus Replication; D014960:X Chromosome