Wounding a fibroblast monolayer results in the rapid induction of the c-fos proto-oncogene.

Abstract

The c‐fos gene has previously been shown to be transiently induced within minutes after the stimulation of mouse fibroblasts with growth factors. Induction of c‐fos was observed specifically with competence factors (e.g., platelet‐derived growth factor), not with progression factors (e.g., platelet‐poor plasma), suggesting a role for c‐fos in conferring competence on fibroblasts. To test this hypothesis we have analyzed c‐fos expression in NIH 3T3 cells that were made competent in a different way, namely by wounding a confluent monolayer of cells. Using antibodies raised against either a synthetic fos peptide or a beta‐galactosidase‐‐fos fusion protein, we show in this study that in the majority of cells lining the wound c‐fos protein is rapidly and transiently induced to high levels. No induction is observed in cells at a distance from the wound greater than approximately 5 cell layers. Induction is equally efficient in both serum‐containing and serum‐free medium, and is similar in cells that were deprived of fetal calf serum for 40 h prior to making the wound. Our observations support the hypothesis that c‐fos may be involved in inducing the ‘competent state’ in fibroblasts and suggests an early role for c‐fos in wound healing and tissue regeneration.