Enhanced expression of c-fos is not obligatory for retinoic acid-induced F9 cell differentiation.

Abstract c- fos was studied in F9 cells to determine whether changes in its expression are an early and/or obligatory event in retinoic acid-induced F9 cell differentiation. Induction of c- fos transcripts was not observed at times early or late during retinoic acid-promoted differentiation, but a decrease in c- myc mRNA was noted as early as l h after retinoic acid dosing. Induction of a rapid and transient change in c- fos expression in F9 cells was observed only in response to serum stimulation. Therefore, although expression of c- fos may be involved in the cellular growth and proliferation of F9 cells, as indicated by the response to serum, an increase in c- fos is not required for retinoic acid-induced differentiation.