Abstract
HTG2 hamster cells produce a defective murine sarcoma virus lacking gp70 and, consequently, viral surface projections (knobs), but the lack of knobs appears to have no effect on intramembrane particle distribution. The core of the virus remains in the immature form as a result of the failure of the polyprotein precursor (p65) to undergo cleavage. Incubation of HTG2 virus with avian myoblastosis virus yields specific cleavage products of p65.