Induction of Collagen Synthesis in Response to Adhesion and TGFβ is Dependent on the Actin-Containing Cytoskeleton
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Adhesive interactions between cells and the extracellular matrix (ECM) are thought to influence gene expression. Previously, we showed that the regulation of α1(I) collagen expression is anchorage-dependent in Swiss 3T3 fibroblasts (Dhawan and Farmer, 1990). Non-adhesive culture conditions established by suspending cells in methylcellulose containing media result in a suppression of procollagen synthesis. Replating these suspended cells onto a tissue culture dish surface rapidly activates procollagen synthesis, and serum factors are not required for this response. The changes in type I procollagen synthesis reflect the levels of α1(I) collagen mRNA. Induction of procollagen synthesis during replating is the result of regulation at transcriptional and post-transcriptional sites (Dhawan et al., 1991). Collagen mRNAs are destabilized in suspended cells and restabilized when adhesive contacts are restored. Transcription of the α1(I) collagen gene is suppressed in suspended cells and reactivated by 18 hours after reattachment. In addition, the 5’ flanking region of the rat α1(I) collagen gene was found to contain sequences that conferred adhesion-responsiveness to a CAT reporter gene.
KeywordsCollagen Synthesis Collagen Gene Serum Response Factor Adhesive Interaction Collagen Expression
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