Maintenance DNA methylation in pre-meiotic germ cells regulates meiotic prophase by facilitating homologous chromosome pairing

ABSTRACT Heterochromatin-related epigenetic mechanisms, such as DNA methylation, facilitate pairing of homologous chromosomes during the meiotic prophase mammalian spermatogenesis. In pro-spermatogonia, de novo methylation plays a key role in completing and initiating division. However, maintenance regulation meiosis, especially adult, is not well understood. Here, we reveal that NP95 (also known UHRF1) DNMT1 – two essential proteins for are co-expressed spermatogonia necessary meiosis male germ cells. We find Np95- or Dnmt1-deficient spermatocytes exhibit spermatogenic defects characterized by synaptic failure prophase. addition, assembly pericentric heterochromatin clusters early prophase, phenomenon required subsequent chromosomes, disrupted both mutants. Based on these observations, propose established pre-meiotic spermatogonia, regulates synapsis and, turn, quality control Maintenance therefore, ensuring faithful transmission genetic information to offspring.