Lineage-specific functions of TET1 in the postimplantation mouse embryo

Kian Peng Koh and colleagues report that TET1 regulates lineage-specific genes in the mouse postimplantation embryo, many of them independently of DNA methylation changes, through regulation of JMJD8 expression. They show that Tet1 deletion causes embryonic defects, which are partially penetrant in an inbred strain but fully lethal in non-inbred mice.