THE PLACENTA GROWTH-FACTOR GENE OF THE MOUSE

Placenta growth factor (PIGF) and vascular endothelial growth factor ( VEGF) are angiogenic factors containing the 8-cysteine motif of platel et-derived growth factor (PDGF). Both PIGF and VEGF are mitogens for e ndothelial cells in vitro and promote neoangiogenesis in vivo. In addi tion, PIGF strongly potentiates the proliferative and the permeabiliza tion effects exerted by VEGF on the vascular endothelium. We have now isolated the cDNA coding for mouse Plgf by screening a mouse heart cDN A library with the human PIGF sequence as probe. The human PIGF protei n has two forms, P1GF-1 and PIGF-2, that arise from alternative splici ng of a single gene mapping on Chromosome (Chr) 14; the isolated mouse PlgfcDNA encodes the longer of these two forms (PIGF-2). We show that the mouse Plgf-2 mRNA is the only transcript present in the normal ti ssues analyzed. Mouse Plgf-2 is a 158-amino-acid-long protein that sho ws 78% similarity (65% identify) to the human P1GF-2. Computer analysi s reveals a putative signal peptide and three probable N-glycosylation sites, two of which are also conserved in human PIGF. The mouse Plgf gene was isolated and characterized; the gene is encoded by 7 exons sp anning a 13-kb DNA interval. Finally, we have mapped the mouse Plgf ge ne to Chr 12, one cM from D12Mit5, and the human PIGF gene to 14q24, u sing both FISH and genetic crosses.