Regulation of m⁶A Transcripts by the 3ʹ→5ʹ RNA Helicase YTHDC2 Is Essential for a Successful Meiotic Program in the Mammalian Germline

N⁶-methyladenosine (m⁶A) is an essential internal RNA modification that is critical for gene expression control in most organisms. Proteins with a YTH domain recognize m⁶A 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 m⁶A reader that is essential for male and female fertility in mice. High-throughput mapping of the m⁶A transcriptome and expression analysis in the Yhtdc2 mutant testes reveal an upregulation of m⁶A-enriched transcripts. Our biochemical studies indicate that YTHDC2 is an RNA-induced ATPase with a 3ʹ→5ʹ RNA helicase activity. Furthermore, YTHDC2 recruits the 5ʹ→3ʹ 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 m⁶A-modified germline transcripts to maintain a gene expression program that is conducive for progression through meiosis. Wojtas et al. show that the cytoplasmic m⁶A “reader” and 3ʹ→5ʹ RNA helicase YTHDC2 is essential for regulating m⁶A transcripts to ensure a successful meiotic gene expression program in the mammalian germline, and that this is essential for male and female fertility.