Potent transcriptional repressor that binds to the H1 element of the Ets2 promoter. May regulate other genes involved in cellular proliferation (By similarity). Required for extraembryonic ectoderm differentiation, ectoplacental cone cavity closure, and chorioallantoic attachment. May be important for regulating trophoblast stem cell differentiation. Expressed along the osteogenic margins of the developing calvarial bones, in a similar distribution to that observed for the master osteogenic regulator RUNX2. Expressed throughout embryonic development and adulthood. In the developing placenta, after 7.5 dpc expression is restricted to the extraembryonic ectoderm, and after 9.5 dpc to subpopulation of labyrinth cells. Phosphorylated by multiple kinases including MAPK1/ERK2 at THR-529. Phosphorylation regulates the activity of ERF (By similarity). Mice fail to undergo chorioallantoic attachment and labyrinth development and die in utero due to severe placenta defects. Belongs to the ETS family. Extended N-terminus. Extended N-terminus.