Interleukin-1 or phorbol induction of the stromelysin promoter requires an element that cooperates with AP-1.

Interleukin-1, a mediator of inflammation, or tumor promoting phorbol esters induce transcription of stromelysin, a metalloproteinase that degrades extracellular matrix molecules and that is overexpressed in diseases such as rheumatoid arthritis. Sequences required for induction of transcription of the human stromelysin promoter are contained on a 46 base pair fragment. This fragment contains a sequence with a high degree of similarity to the binding site for the transcription factor activator protein-1 (AP-1) and indeed, the AP-1 sequence of this fragment is necessary but not sufficient for the maximal response to phorbol 12-myristate 13-acetate (phorbol) or interleukin-1. Maximal induction requires functional cooperation between the AP-1 sequence and a neighboring upstream regulatory sequence (URS) of the stromelysin promoter which is also necessary but not sufficient. We demonstrate that both the AP-1 sequence and the URS bind phorbol or interleukin-1 induced nuclear proteins. Cooperation of the AP-1 sequence with another sequence present in the stromelysin promoter may be a general mechanism whereby the AP-1 element, which is found in many promoters, achieves a maximal and specific response to various stimuli.