Regulation of m6 A Transcripts by the 3' → 5' RNA Helicase YTHDC2 Is Essential for a Successful Meiotic Program in the Mammalian Germline

N-6-methyladenosine (m(6)A) is an essential internal RNA modification that is critical for gene expression control in most organisms. Proteins with a YTH domain recognize m(6)A marks and are mediators of molecular functions like RNA splicing, mRNA decay, and translation control. Here we demonstrate that YTH domain-containing 2 (YTHDC2) is an m (6)A reader that is essential for male and female fertility in mice. High-throughput mapping of the m 6 A transcriptome and expression analysis in the Yhtdc2 mutant testes reveal an upregulation of m 6 A-enriched transcripts. Our biochemical studies indicate that YTHDC2 is an RNA- induced ATPase with a 3' -> 5' RNA helicase activity. Furthermore, YTHDC2 recruits the 5' -> 3' exoribonuclease XRN1 via Ankyrin repeats that are inserted in between the RecA modules of the RNA helicase domain. Our studies reveal a role for YTHDC2 in modulating the levels of m(6) A-modified germline transcripts to maintain a gene expression program that is conducive for progression through meiosis.