Isolation of the human platelet glycoprotein IIb gene and characterization of the 5' flanking region.

ABSTRACT

Platelet membrane glycoprotein (GP) IIbIIIa complex functions as a receptor for fibrinogen, von Willebrand factor and fibronectin, and mediates adhesive reactions of platelets. The gene for the GPIIb subunit is only active in megakaryocytic cell type. We have isolated this gene from a genomic library. The GPIIb gene was characterized by restriction mapping and sequencing of the 5' and 3' regions containing the first and the last exons. The transcription start site and the polyadenylation signal were identified. From these data we deduced that the gene spans a region of 22 kb and that the mRNA contains a leader sequence of 32 nucleotides. At the 3' end the last exon encodes the 19 amino acids corresponding to the cytoplasmic domain of the GPIIb light chain. Upstream the transcription start site, two sequences are homologous to consensus binding sites of the nuclear factors SP1 and CP2. Two inverted repeats were also identified in this region.