In mouse development, differentiation of the inner cell mass (ICM) and trophectoderm (TE) during the transition from the morula to blastocyst stage is regulated by the Hippo pathway; however, the functions of the Hippo pathway in porcine embryogenesis have not been investigated. In the present study, we examined the gene expression patterns of the Hippo pathway members yes-associated protein 1 (YAP1) and large tumor suppressor 2 (LATS2) and the functions of these genes during porcine preimplantation development using RNA interference. Both YAP1 and LATS2 mRNA levels were shown high in the in vitro matured oocytes and 1-cell stage embryos and fell progressively with development. YAP1 nuclear localization was detected at the morula and blastocyst stages. Downregulation of either YAP1 or LATS2 inhibited porcine preimplantation development and affected the expression levels of POU class 5 homeobox 1 (OCT-4) and SRY-related HMG-box gene 2 (SOX2), transcription factors necessary for the ICM/TE differentiation. Taken together, YAP1 and LATS2 are essential for porcine preimplantation development, and it is possible that the Hippo pathway has important roles in porcine ICM/TE segregation.
Keywords: Hippo pathway; IVF; early development; embryo; porcine.