NewslettersESC & iPSC News Zygotic Genome Activation by the Totipotency Pioneer Factor Nr5a2 By Noshin Noorjahan - November 30, 2022 0 Based on de novo motif searches, scientists identified the orphan nuclear receptor Nr5a2 as a key activator of major zygotic genome activation in mouse 2-cell embryos. Nr5a2 was required for progression beyond the 2-cell stage. [Science] Abstract