Regulation of human coagulation factor X gene expression by GATA-4 and theSp family of transcription factors

Serine protease factor Xa plays a critical role in the coagulation cascade, Zymogen factor X is synthesized and modified in the liver. To understand t he mechanisms governing the liver-specific expression of factor X, the prox imal promoter of human factor X was previously characterized. Two crucial c is elements at -73 and -128 and their cognate binding proteins, HNF-4 and N F-Y, respectively, were identified. In this report, studies are extended to 3 additional cis elements within the factor X promoter. Using gel mobility shift assays, the liver-enriched protein GATA-4 was identified as the prot ein binding to the GATA element at -96, GATA-4 transactivates the factor X promoter 28-fold in transient transfection experiments. It was also determi ned that the Sp family of transcription factors binds 2 DNase I-footprinted sites at -165 and -195, Disruption of Sp protein binding at either site re duces the promoter activity by half, Simultaneous disruption of both sites reduces the promoter activity 8-fold. This is the first report indicating t he involvement of GATA-4 in the regulation of clotting factor expression. T hese observations provide novel insight into mechanisms by which the vitami n K-dependent coagulation factors are regulated. (C) 2001 by The American S ociety of Hematology.