Analysis of the virions released from CV-1 cells transfected/infected with either SV40(776) WT or its Pt mutant. CV-1 cells were transfected with either SV40(776) WT or Pt mutant genome and supernatants from infected cells were collected at time points indicated for analysis of the released virions by Western blot for VP1 (A) and Southern blotting (B) as described for the figure legends for Figure. 7A. and Figure. 8B respectively. In lane 1 in panel A, supernatant from uninfected cells was immunoprecipitated with anti-VP1 antibody and loaded as a negative control (- Cont.). In lane 1 in panel B, SV40(776) genome (2 ng) digested with BamH I was loaded as a positive control (+ Cont.).