Theinhibition of p53 expression did not alter the cell cycle arrest induced byoncogenic N-RASQ61K (15 days after infection only 5% of N-RASQ61Kmelanocytes showed positive Ki67 staining regardless of p53 expression and thiscan be compared to 23% Ki67 positive p53-null melanocytes infected with thecopGFP control; Figure 3A). Here, MKI67 is linked to infection.