Inhibition of rabbit collagenase (matrix metalloproteinase-1; MMP-1) transcription by retinoid receptors: evidence for binding of RARs/RXRs to the -77 AP-1 site through interactions with c-Jun.
Treatment of synovial fibroblasts with retinoic acid (RA) decreases their expression of collagenase (matrix metalloproteinase-1 or MMP-1), an enzyme that degrades interstitial collagens and contributes to the pathology of rheumatoid arthritis. This inhibition results, at least in part, from RA-induced decreases in the mRNA for the transactivators Fos and Jun (with concominant increases in RAR mRNA) and by sequestration of Fos/Jun by RARs/RXRs. Previously, we provided evidence that retinoid receptors are also present in complexes that bind to fragments of rabbit MMP-1 promoter DNA containing an AP-1 site at -77 (Pan et al., 1995, J. Cell. Biochem., 57:575-589). However, it was unclear whether RARs and retinoid X receptors (RXRs) were binding directly to the DNA or indirectly through another protein. We now use a sensitive MMP-1 promoter/luciferase reporter construct to confirm the transcriptional role of the AP-1 site at -77. In addition, with electrophoretic mobility shift analyses (EMSAs), antibody "supershifts" and DNAase 1 footprinting, we examine the interaction of retinoid receptors and AP-1 protein on the MMP-1 promoter. We demonstrate that RARs, RXRs, and c-Jun form a complex at the AP-1 site in which c-Jun binds directly to the DNA and apparently tethers the retinoid receptors to the complex. We conclude that retinoid receptors/AP-1 protein interactions at the DNA may provide an additional means of controlling collagenase gene transcription by retinoids.
Department of Medicine, Dartmouth Medical School, Hanover, New Hampshire 03755, USA.
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Schroen
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Brinckerhoff
D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D017364:Collagenases / Q000235:genetics / Q000378:metabolism*; D018983:DNA Footprinting; D015342:DNA Probes / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D005786:Gene Expression Regulation / Q000235:genetics; D017930:Genes, Reporter / Q000235:genetics; D005822:Genetic Vectors; D020781:Matrix Metalloproteinase 1; D061965:Matrix Metalloproteinase Inhibitors; D009687:Nuclear Proteins / Q000378:metabolism / Q000494:pharmacology; D011401:Promoter Regions, Genetic / Q000235:genetics; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism / Q000494:pharmacology; D011817:Rabbits; D018168:Receptors, Retinoic Acid / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013582:Synovial Fluid / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects*; D014162:Transfection / Q000235:genetics; D014212:Tretinoin / Q000494:pharmacology
D015342:DNA Probes; D061965:Matrix Metalloproteinase Inhibitors; D009687:Nuclear Proteins; D016755:Proto-Oncogene Proteins c-jun; D018168:Receptors, Retinoic Acid; D011994:Recombinant Proteins; D014212:Tretinoin; D017364:Collagenases; D020781:Matrix Metalloproteinase 1; D013755:Tetradecanoylphorbol Acetate