OCT4 expression transactivated by GATA protein is essential for non-rodent trophectoderm early development.

Oct4 is exclusively expressed in rodent inner cell mass (ICM) but silenced in its trophectoderm (TE). However, for many non-rodent animals, including pig, cattle, rabbit, goat, and human, OCT4 has a remarkable expression in early TE. This study, applying pig as the main research model, proves that OCT4 expression in TE is supported by a unique GATA motif in the OCT4 upstream conserved regulatory region, and GATA4 is responsible for its activation. Moreover, OCT4 acts as a specific regulator of a narrow range of genes (including BCL2A1 and HNRNP2AB1) that are essential for the first wave of rapid proliferation in early TE. This study describes the regulatory mechanism to direct the OCT4 expression and its significance in TE of porcine preimplantation embryo. [Display omitted] • GATA4 binds to OCT4 upstream of CR4 to support OCT4 prolonged expression in porcine TE • Variation of TCFAP2 motif does not cause prolonged OCT4 expression in porcine TE • CDX2 fails to downregulate OCT4 in porcine early TE due to stable CDX2/OCT4 ratio • OCT4 is essential for the rapid proliferation of porcine TE OCT4 expression is maintained in early TE of many non-rodent animals, but its molecular basis and significance remain elusive. Bou et al. demonstrate that, in porcine TE, GATA4 transcriptionally activates OCT4 to guarantee TE rapid proliferation and emphasize the importance of embryonic studies in more species. [ABSTRACT FROM AUTHOR]