TEMPERATURE-SENSITIVE MUTANT P53 (ALA143) INTERFERES TRANSIENTLY WITHDNA-SYNTHESIS AND CELL-CYCLE PROGRESSION IN SAOS-2 CELLS

It has been demonstrated that temperature-sensitive mutant p53 (val--> ala143) inhibits cell-proliferation at the permissive temperature, alb eit to a lesser extent than wild-type p53 (Zhang et al.: EMBO J 13:253 5-2544, 1994). We have studied its effect on the cell-cycle by dual-pa rameter now cytometry, extended pulse-labeling, and pulse-chase experi ments. p53(ala143) interferes in Saos-2 cells at three levels with cel l-cycle progression at permissive temperatures: it caused a G1-arrest, a reduced rate of DNA synthesis during S, and a prolonged G2/M. Strik ingly, all these effects are transient. Continued culturing at 32 degr ees C resulted in normal cell-cycle progression. Abrogation of the G1- block occurred even in the presence of high p21(Waf1) protein levels, a negative cell-cycle regulator of which the expression is induced by wild-type p53. (C) 1996 Wiley-Liss, Inc.