Mettl3-catalyzed mA regulates histone modifier and modification expression in self-renewing somatic tissue.

-methyladenosine (mA) is the most abundant modification on messenger RNAs (mRNAs) and is catalyzed by methyltransferase-like protein 3 (Mettl3). To understand the role of mA in a self-renewing somatic tissue, we deleted in epidermal progenitors in vivo. Mice lacking demonstrate marked features of dysfunctional development and self-renewal, including a loss of hair follicle morphogenesis and impaired cell adhesion and polarity associated with oral ulcerations. We show that Mettl3 promotes the mA-mediated degradation of mRNAs encoding critical histone modifying enzymes. Depletion of Mettl3 results in the loss of mA on these mRNAs and increases their expression and associated modifications, resulting in widespread gene expression abnormalities that mirror the gross phenotypic abnormalities. Collectively, these results have identified an additional layer of gene regulation within epithelial tissues, revealing an essential role for mA in the regulation of chromatin modifiers, and underscoring a critical role for Mettl3-catalyzed mA in proper epithelial development and self-renewal.