G2E3 is a dual function ubiquitin ligase required for early embryonic development.

G2E3 is a putative ubiquitin ligase (E3) identified in a microarray screen for mitotic regulatory proteins. It shuttles between the cytoplasm and nucleus, concentrating in nucleoli and relocalizing to the nucleoplasm in response to DNA damage. In this study, we demonstrate that G2E3 is an unusual ubiquitin ligase that is essential in early embryonic development to prevent apoptotic death.