m6A mRNA Methylation Facilitates Resolution of Naïve Pluripotency Towards Differentiation (Ribo-seq). Mus musculus

Naïve and primed pluripotent states retain distinct molecular properties, yet limited knowledge exists on how their state transitions are regulated. Here we identify Mettl3, an N6-Methyladenosine (m6A) transferase, as a regulator for terminating murine naïve pluripotency. Mettl3 knockout pre-implantation epiblasts and naïve embryonic stem cells (ESCs) are depleted for m6A in mRNAs and yet, are viable. However, they fail to adequately terminate their naïve state, and subsequently undergo aberrant and restricted lineage priming at the post-implantation stage, leading to early embryonic lethality. m6A predominantly and directly reduces mRNA stability, including that of key naïve pluripotency promoting transcripts. This study highlights a critical role for an mRNA epigenetic modification in vivo, and identifies regulatory modules that functionally influence naïve and primed pluripotency in an opposing manner. Overall design: Ribosome footprint (Ribo-Seq) was measured from mouse embryonic stem cells and mouse embriod bodies, in WT and Mettl3-KO cell lines.