FIG. 9.

Southern blot analysis of FeLV-B proviral DNAs in tumors induced by intradermal inoculation with 61E/945SL (cats N65 and N67) or intraperitoneal inoculation with 61E/945L (cat O27), 61E/945SL (cats N90, N91, and N92), or FeLV-A/61E (cat O4). DNA samples from the tumor (lanes T) or control uninvolved tissue from the same animal (lanes C) were digested with KpnI and hybridized to a Sau3A probe (B/S) derived from the env gene of FeLV-B/Gardner-Arnstein (35). The presence of recombinant FeLV-B proviral DNA in tumors from cats N67 and O4 is evident as a novel hybridizing fragment of ∼3.6 kb that is distinct from endogenous FeLV-related sequences (asterisks).