DIFFERENT MECHANISMS OF REGULATION OF THE HUMAN STROMELYSIN AND COLLAGENASE GENES - ANALYSIS BY A REVERSE-TRANSCRIPTION-COUPLED-PCR ASSAY

Tissue-remodeling processes are largely controlled by matrix metallopr oteinases that degrade the extracellular components of connective tiss ues. In this study, gene regulation of two human matrix metalloprotein ases, stromelysin and collagenase, was investigated by a reverse-trans cription-coupled (RT)-PCR assay. Here, signals from both the heterogen ous nuclear RNA (hnRNA) and mRNA are amplified, allowing the regulatio n of gene expression to be divided between transcriptional and/or post -transcriptional control. In confluent human lung fibroblast cultures, tumor-necrosis factor-alpha and 12-O-tetradecanoyl-phorbol 13-acetate induce stromelysin and collagenase genes transcriptionally. Interleuk in-1 beta (IL-1 beta) induces stromelysin gene transcription but has l ittle, if any, effect on the collagenase gene transcription in cells c ultured in the presence of 10% serum. By a competitive RT-PCR assay, t he IL-1 beta-reated cultures contain an average of 60 molecules of str omelysin mRNA/cell and the untreated cultures about 1.9 molecules/cell . In serum-starved cells, both IL-1 beta and serum induce transcriptio n of the collagenase gene. Also, in serum-starved cells type Il collag en can induce collagenase mRNA but not stromelysin mRNA. Inhibition of protein synthesis with cycloheximide induces stromelysin gene transcr iption but has no effect on the collagenase gene. These data indicate different mechanisms of regulation of the human stromelysin and collag enase genes in cultured eels.