Abstract
We studied early changes in gene expression during fibroblast contraction of stressed collagen matrices. The level of c-
fos
mRNA increased dramatically and peaked 50 to 60 min after matrix contraction was initiated. This response did not require serum and could not be accounted for simply by disruption of the actin cytoskeleton. Increased c-
fos
mRNA levels required Ca
2+
influx but not the cyclic AMP or extracellular signal-regulated kinase (ERK 1/2) signaling pathways, both of which are activated when fibroblasts contract stressed collagen matrices. The levels of two other immediate-early genes,
fosb
and c-
jun
, also increased transiently after fibroblast contraction, whereas the levels of
fra-1
,
fra-2
, c-
myc
, and the transcription factor NF-κB remained the same, indicating that fibroblast contraction caused changes in a selective group of genes. The increase in c-
fos
mRNA during contraction of stressed collagen matrices may reflect a unique role for c-
fos
in mechanoregulated events at the end of wound repair.
