m6A Reader hnRNPA2B1 Modulates Late Pachytene Progression in Male Meiosis Through Post-Transcriptional Control.

N6-methyladenosine (m6A) reader proteins have been demonstrated to be involved in numerous biological processes. However, the regulatory mechanism of specific m6A reader proteins during mammalian meiotic processes remains largely elusive. Here, this study identified hnRNPA2B1 as an m6A reader protein that plays a critical role in meiotic pachytene progression using a tamoxifen-induced knockout mouse model. Deletion of hnRNPA2B1 in spermatocytes disrupts homologous recombination and synapsis, with the mislocalization of double-strand break (DSB) repair proteins beyond the chromosome axes in pachytene spermatocytes. Multi-omics analyses revealed extensive dysregulation of the transcriptome and proteome in hnRNPA2B1-deficient spermatocytes, particularly affecting genes involved in chromosome organization, meiotic cell cycle, and DNA damage response, thereby triggering the pachytene checkpoint for cell elimination. In vitro luciferase assays confirmed that hnRNPA2B1 directly targets several meiosis-related transcripts (e.g., Ep400, Rrs1, etc.) in an m6A-dependent manner to regulate their expression. Furthermore, this finding demonstrates that hnRNPA2B1 biologically interacts with mRNA processing regulators and translation factors (e.g., eIF4G3, RPS3, RPL13, DDX5, YTHDC2) and functions as a post-transcriptional factor essential for pachytene progression during male meiosis. Collectively, this study underscores the critical role of the m6A reader hnRNPA2B1 in the pachytene checkpoint and advances our understanding of the regulatory mechanisms underlying male meiosis.