PLAC1, an Xq26 gene with placenta-specific expression

A novel human X-linked gene shows placenta-specific expression and has been named PLAC1. The gene maps 65 kb telomeric to HPRT at Xq26 and has been co mpletely sequenced at the cDNA and genomic levels. The mouse orthologue Pla c1 maps to the syntenically equivalent region of the mouse X chromosome. In situ hybridization studies with the antisense mRNA during mouse embryogene sis detect Plac1 expression from 7.5 dpc (days postcoitum) to 14.5 dpc in e ctoplacental cone, giant cells, and labyrinthine trophoblasts. The putative human and murine PLAC1 proteins are 60% identical and 77% homologous, Both include a signal peptide and a peptide sequence also found in an interacti on domain of the ZP3 (zona pellucida 3) protein. These results make PLAC1 a marker for placental development, with a possible role in the establishmen t of the mother-fetus interface. (C) 2000 Academic Press.