Placenta Specific Protein 1 (PLAC1)

Cocchia et al. (2000) isolated a novel gene, which they designated PLAC1, approximately 65 kb telomeric of the HPRT gene. The mouse homolog was also found to map near Hprt on the X chromosome. Human PLAC1 is transcribed in the telomeric to centromeric direction, opposite to the orientation of HPRT, and contains 3 predicted exons. It encodes a deduced 212-amino acid protein that shares 60% sequence identity with mouse Plac1. The human and mouse proteins contain a signal peptide and a ZP3 motif. Northern blot analysis detected placenta-restricted expression of a 1.7-kb PLAC1 mRNA transcript. In situ hybridization studies in mouse detected Plac1 expression from 7.5 to 14.5 days postcoitum in ectoplacental cone, giant cells, and labyrinthine trophoblasts.