THE ENDOGENOUS MTV-8 PROVIRUS RESIDES WITHIN THE V KAPPA LOCUS

The endogenous Mtv-8 provirus previously has been mapped within approximately 0.52 centimorgan from several V(k) markers on mouse chromosome 6. Using Southern blotting and DNA from a recombinant backcross mouse from the C57BL/6 (Mtv-8 positive) and C58 (Mtv-8 negative) strains, Mtv-8 was localized to the same side of the crossover point as immunoglobulin kappa (Igk)-V24 but on the opposite side of the crossover from Igk-V10 and Igk-V21. Molecular cloning and characterization of cellular DNA adjacent to Mtv-8 revealed a functional V(k)9 gene approximately 4.6 kb downstream and in the same transcriptional orientation as the provirus. These data suggest that Mtv-8 is within the centromere-proximal portion of the V(k) locus.