REGULATION OF THE TISSUE FACTOR PROMOTER IN ENDOTHELIAL-CELLS - BINDING OF NF-KAPPA-B-LIKE, AP-1-LIKE, AND SP1-LIKE TRANSCRIPTION FACTORS

Tissue factor is up-regulated on endothelial cells and monocytes in re sponse to cytokines and endotoxin and is the main trigger of the extri nsic pathway of the coagulation cascade. We have isolated the porcine tissue factor gene and studied the regulation of the promoter, which h as not been investigated previously in endothelial cells. Comparison o f the promoter sequences with the respective human and murine genes re veals short stretches of homology, which encompass potential binding s ites for AP-1, NF kappa B, and Spl transcription factors. Using DNase I footprinting, we detect binding of nuclear factors to these promoter elements. Transfection experiments demonstrate that a 300-base pair f ragment containing the conserved elements can mediate induced transcri ption and that the NF kappa B-like element is essential, In accordance , electrophoretic mobility shift assays show a strong increase in the binding of factors to the NF kappa B-like site following induction. We further provide evidence that RelA (p65), c-Rel, and possibly novel p olypeptides bind to the tissue factor NF kappa B element, In addition, we show constitutive binding of members of the Fos/Jun and Spl famili es to the AP-1 and Spl sites, respectively, We propose a concerted act ion of AP-1-, NF kappa B-, and Spl-like factors in transcription from the tissue factor promoter in endothelial cells,