By Irene Hsiao
How maternally supplied mRNAs are degraded in a developing embryo, which then functions under its newly activated zygotic genome, has been a poorly understood process in the key developmental stage known as the maternal-to-zygotic transition. Using zebrafish as a model, graduate student Boxuan Zhao and others in Professor Chuan He’s lab worked alongside Professor Robert Ho's group in the Department of Organismal Biology and Anatomy to find that about a third of maternal mRNAs are subject to modification by N6-methyladenosine (m6A). The addition of m6A marks mRNA for clearance by a protein discovered by the He lab in 2014. Their findings, published in Nature 13 February 2017, provide insight into the processes that determine cell identity and the mechanisms of transcriptome switching during early embryonic development.