Coordinate induction of fibronectin, fibronectin receptor, tropomyosin, and actin genes in serum-stimulated fibroblasts.

From a collection of more than 80 nonoverlapping clones, isolated by differential screening of a lambda cDNA library prepared from serum-stimulated cells in the presence of cycloheximide, we have identified four clones that encoded for components of the cytoskeleton and extracellular matrix. DNA sequencing of clones B2, V58, TT1, and P38 demonstrated that they corresponded to beta-actin, alpha-tropomyosin, fibronectin, and the beta-subunit of fibronectin receptor. All four mRNA levels showed a detectable increase 30 min after stimulation and remained at high levels for at least 8 h. The half-lives of these mRNAs were found to be very long in contrast to those of other growth factor-inducible genes. An increase in transcription was observed for the four genes. Actin and fibronectin showed nearly maximal increase at 15 min, while fibronectin receptor and tropomyosin reached their maximum transcription at 1 h. These results demonstrated that four interacting components of the cytoskeleton and extracellular matrix are rapidly induced in stimulated quiescent cells, possibly reflecting part of the coordinate changes in gene expression that occur during embryogenesis and wound healing.