RESUMO
A fragment of the 5' untranslated region corresponding to the canine matrix metalloproteinase-13 (MMP-13), collagenase-3 gene promoter has been isolated and characterized in rat cardiocytes to investigate the role of MMP-13 in cardiac disease. The promoter fragment (1.5 kb) demonstrated regions of sequence homology with the collagenase gene promoter sequences already determined for other species. Conserved regions were identified and shown to correlate with DNA binding motifs including AP-1 sites, a nuclear factor (NF) B-like binding domain, GATA and Nkx2.5 sites. A consensus TATA box was identified and shown to direct transcription initiation approximately 27 bp upstream of the translation start site. The canine MMP-13 promoter fragment was sufficient to drive basal expression of a luciferase reporter gene in both Madin Darby canine kidney cells (MDCK) and primary rat cardiocytes. The activity of the promoter fragment could be significantly increased by the treatment of transfected primary rat cardiocytes with interleukin-1 (IL-1) and basic fibroblastic growth factor (bFGF), with some induction also observed with tumour necrosis factor (TNF). The canine MMP-13 promoter activity has also been compared to the basal and induced activity of the canine MMP-9, gelatinase B promoter in these cell types.
