Ribo-seq data of spermatocytes

Meiosis in males is a critical process that ensures complete spermatogenesis and genetic diversity. However, the key regulators involved in this process and the underlying molecular mechanisms remain unclear. Here, we report that the m6A methyltransferase METTL16 plays an essential role in meiotic sex chromosome inactivation (MSCI), double-stranded break (DSB formation), homologous recombination, and SYCP1 deposition during male meiosis. Depletion of METTL16 results in the failure of MSCI establishment and maintenance, leading to significant deregulation of the transcriptome in pachytene spermatocytes, where approximately 80% of the differentially expressed genes (DEGs) on sex chromosomes undergo upregulation. Furthermore, METTL16 deficiency also causes reduced DSB formation and recombination, and increased deposition of SYCP1 during the first wave of spermatogenesis. Mechanistically, in pachytene spermatocytes, METTL16 interacts with MDC1/SCML2 to coordinate DNA damage response (DDR) and epigenetic modifications of the XY body that establish and maintain MSCI, and in early meiotic prophase I, METTL16 regulates DSB formation and recombination by regulating the protein levels of meiosis-related genes. Furthermore, RIP-Seq, MeRIP-Seq, and IP-MS analyses reveal that METTL16 interacts with the translation factors eIF3B/eIF4A3/eIF4G3 in early meiotic prophase I spermatocytes and controls m6A levels in the RNAs of meiosis-related genes (e.g., Ubr2) to regulate meiosis progression in male mice. Collectively, our study identified METTL16 as a previously unknown key regulator of meiosis in males and demonstrated that it plays an essential role in meiosis by interacting with MSCI-related factors and regulating m6A levels and translation efficiency of meiosis-related genes.