Placenta growth factor (PlGF) is a member of the vascular endothelial growth factor (VEGF) family of growth factors. PlGF and VEGF share primary structural as well as limited amino acid sequence homology with the A and B chains of PDGF. All eight cysteine residues involved in intra-and inter-chain disulfides are conserved among these growth factors. As a result of alternative splicing, three PlGF RNAs encoding monomeric human PlGF-1, PlGF-2 and PlGF-3 isoform precursors containing 149, 179 and 219 amino acid residues, respectively, have been described.
In normal mouse tissues, only one mouse PlGF mRNA encoding the equivalent of human PlGF-2 has been identified. Mouse PlGF-2 encodes a 158 amino acid residue precursor protein. Mouse PlGF-2 shares 65% amino acid identity with human PlGF-2. The gene for PlGF has been mapped to mouse chromosome 12 and human chromosome 14.