The necessity of TEAD4 for early development and gene expression involved in differentiation in porcine embryos.

TEA domain family transcription factor 4 (Tead4) is known to be important for the trophectoderm (TE) segregation in murine embryos. However, the role of TEAD4 in early development of porcine embryos is still unknown. We examined TEAD4 expression patterns and attempted to determine the functions of TEAD4 during porcine preimplantation development using RNA interference. TEAD4 mRNA was upregulated from the 2-4-cell to 8-16-cell stages and then decreased to the blastocyst stage. Nuclear localization of TEAD4 protein was detected at the 16-cell stage, as well as at subsequent developmental stages. In porcine embryos injected with TEAD4 siRNA, transformation from morula to blastocyst was inhibited. Although TEAD4 downregulation did not affect the expression levels of POU class 5 homeobox 1 (OCT-4), transcription of SRY-related HMG-box gene 2 (SOX2) was detected at high level in TEAD4-downregulated embryos. It is possible that TEAD4 contributes to blastocyst formation in porcine embryos through downregulation of SOX2 expression. Collectively, our results indicate that TEAD4 is an important factor for the preimplantation development of porcine embryos.