Molecular cloning of pig ZPBP2 and mRNA expression of ZPBP1 and ZPBP2 in reproductive tracts of boars.

Zona pellucida binding proteins (ZPBPs) are important receptors of zona pellucida on sperm and play an essential role in sperm–egg interaction. In the present study, the full-length coding regions of transcript variant 1 and 2 of ZPBP2 were cloned in the pig. ZPBP1 gene expression was specifically present in testes of boar reproductive tracts; while ZPBP2 mRNA was detected with highly in testes, moderate in seminal vesicles and low in caudal epididymes. We also examined the expression profile of porcine ZPBP1 and ZPBP2 in testes and seminal vesicles at different developmental stages. The results revealed that ZPBP1 mRNA was not detectable until day 70 and kept relative stable from days 70 to 105, then increased sharply from days 105 to 160 during sexual maturity (P<0.01). ZPBP2 mRNA was detected with relative low level until day 70 and but increased significantly from days 70 to 105 (P<0.01), and increased further from days 105 to 160 during sexual maturity (P<0.01). The data indicated that testes are the main origin of ZPBPs and the expression of ZPBPs are parallel with reproduction development.