Transcriptome and miRNA on Pig Reproduction

Reproduction in pigs is one of the most economically important traits. The placental efficiency is one of the major determinants of litter size in pigs. We examined gene and miRNA expression profiles of placenta from Chinese Meishan and Yorkshire pigs collected on days15, 26 and 50 of gestation and identified differentially expressed genes and miRNAs. The genes and miRNAs that are expressed in gestational stage-specific pattern were also investigated. Among them, the expression of some genes, e.g. the PLAC-1 and PLET-1, were strictly limited to cells of trophoblasts lineage on days 15, 26, 50 and 95 of gestation. The integration analyses of the miRNA and mRNA data revealed that the differentially expressed miRNAs may regulate the genes associated with cell adhesion, cytoskeletal reorganization, cell proliferation and angiogenesis. Of them, the miR-200 family and miR-205 might play important role in regulation of expression of genes (such as E-cadherin) involved in uterine luminal and trophoblast epithelial polarity by targeting the ZEB1/ZEB2 genes. Further characterization of the molecular mechanisms underlying porcine placenta development and the genes controlling litter size in pigs are currently in progress.