m6A methylation regulates the fate of endogenous retrovirus transcripts [RIP-seq]

Using a genome-scale CRISPR knockout screening in mouse embryonic stem cells, we identify m6A RNA methylation as an important regulatory component that restricts the activity of endogenous retroviruses of the IAP (intracisternal A-particles) family. The m6A methylation of IAP mRNAs occurs on their 5’ end, is catalyzed by the complex of methyltransferase-like (METTL)3/METTL14 proteins whose depletion, along with other complex subunits, namely WTAP and ZC3H13, leads to increased IAP transcript abundance. Using auxin-dependent degron, we show that rapid removal of METTL3, METTL14 and ZC3H13 further increases IAP RNA abundance in a progressive and reversible fashion. Finally, we demonstrate that m6A RNA reduces the stability of IAP transcripts m6A-seq was measured from total RNA in mouse embryonic stem cells (ESCs) in WT and Mettl3-/- conditions. 3 biological replicates are available for the IP of m6A. One control input was generated per cell condition.