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.

Type C viruses: Natural derivatives of cellular genes involved in malignant transformation

“…Since the initial events in viral infection involve the binding of gp70 to a specific cell receptor, both the nature of the env gene and that of cellular genes which encode receptors regulate whether viruses can penetrate and infect cells. Genes for gp70 receptors are genetically transmitted in mouse DNA [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]20], and while the presence of free receptors is not necessarily sufficient for cellular susceptibility [58,78], cells lacking receptors are resistant to infection. Using a gp70 binding assay [10], receptors for gpT0 can be enumerated and their affinities studied.…”

Chromosomal evolution of the Canidae

“…1981. Briefly, the cell culture fluid from an FeSV-infectcd mink cell line (Mvllu) was filtered and supplemented with 1% polybrenc (O'Brien and Simonson, 1978). This solution was diluted 1:3 with MEM alpha medium (Gibco) and added to subconfluent primary cell lines.…”