Serum-inducible gene expression in fibroblasts.

The proliferation of normal mammalian cells is regulated by external growth factors. The complex array of biochemical events triggered by these factors is believed to be modulated by changes in gene expression and leads to cell growth. The long range goals of this research are to identify, isolate, and characterize the genes that modulate cell growth and to determine the functions of their protein products. Previously, several genes were identified whose expression was characterized as growth-regulated; their cognate cytoplasmic transcripts were induced when quiescent cells were stimulated with serum. Predicated on the fact that only 1% of active genes respond to mitogenic stimulation, we hypothesize that these growth-regulated genes are functionally involved in the mitogenic process. We have identified one of these growth regulated genes by sequence analysis to be annexin II, a major substrate of tyrosine kinases. We have determined that the expression of this gene is growth-regulated and that its membrane/cytoskeleton association changes as a function of mitogenic stimulation.