Cloning of the Genes for Human Stromelysin and Stromelysin 2: Differential Expression in Rheumatoid Synovial Fibroblasts

Stromelysin is a member of a gene family of metalloproteinases involved in extracellular matrix remodeling in normal and diseased processes. Primary cultures of rheumatoid synovial cells produce large amounts of metalloproteinase mRNA and proteins. We cloned a cDNA for human stromelysin from a rheumatoid synovial cell cDNA library, and we used the cDNA to isolate the gene for human stromelysin and a related gene, stromelysin 2. We sequenced parts of the genes and found that both are contained on approximately 14 kilobase pairs of DNA. Using an exon-containing fragment of the stromelysin 2 genomic clone as a specific probe in Northern blot analysis, we demonstrate the differential expression of stromelysin and stromelysin 2 in rheumatoid synovial cells, human foreskin fibroblasts, and rabbit synovial fibroblasts. In addition, using chimeric constructs of the stromelysin promoter linked to the bacterial gene chloramphenicol acetyltransferase (CAT), we show that the elements required for the tumor promoter phorbol myristate acetate (PMA), epidermal growth factor (EGF), and interleukin 1 beta (IL-1 beta) induction are contained on a 307 base pair fragment which includes approximately 270 base pairs (bp) of 5'-flanking DNA. The cloning of the human stromelysin and stromelysin 2 genes, the documentation of their differential expression, and the identification of transcriptional regulatory regions in the stromelysin gene will facilitate the study of metalloproteinase gene expression in normal processes and in diseases such as rheumatoid arthritis.