Effects of ERα-specific antagonist on mouse preimplantation embryo development and zygotic genome activation.

Zygotic genome activation (ZGA) is essential for normal development of mammalian preimplantation embryos. Estrogen receptor alpha (ERα) has been implicated in early embryogenesis, and controls the expression of genes associated with proliferation, differentiation and development of cell and target organs via a genomic effect. The objective of this study was to determine whether ERα plays a role in early embryo development and affects ZGA gene expression. Toward this objective, 1-cell embryos from B6C3F1 mouse were cultured with the antiestrogen ICI182780, ERα-specific antagonist MPP, ERα-specific antibody and ERβ-specific antagonist PHTPP. Development of 2-cell to 4-cell in vitro was significantly blocked by ICI182780, MPP and ERα-antibody treatment in a dose-dependent manner but not affected by PHTPP exposure. MPP decreased nuclear ERα protein levels and reduced mRNA expression levels of MuERV-L, one of the ZGA related genes. The results indicate that ERα has a functional role in early embryo development by regulation of ZGA-related genes.