Rapid activation of p53 in ts13 cells. ts13 (A, B, and C) and ts13R (C) cells were cultured at 33.5°C (time zero) or 39.5°C for the indicated periods of time. Equal amounts of lysates were separated by SDS-polyacrylamide gel electrophoresis, transferred to nitrocellulose, and probed with the indicated antibodies. Cyc., cyclin; Tub., tubulin.