P53 GENE IS UP-REGULATED DURING SKELETAL-MUSCLE CELL-DIFFERENTIATION

Differentiation of cells in the mouse myogenic cell line C2, or a primary culture of chicken satellite cells was induced by low serum levels in the growth medium. Endogenous wild-type p53 mRNA was substantially expressed after approximately 5 h of incubation. Induction of p53 mRNA expression was also observed in cells treated with 10-8 M retinoic acid, after 18 h of incubation. In both cases, the increase in p53 mRNA was transient. c-fos mRNA levels decreased rapidly and were barely detectable after 2 h of exposure to retinoic acid. The down-regulation of c-fos confirms its role in muscle cell differentiation, whereas the up-regulation of wild-type p53 suggests its role during this process. © 1993 Academic Press, Inc.