The methyltransferase N6amt1 regulates hippocampal neurogenesis through 6 mA modification of Txnrd3 DNA.

N6-methyladenine (6 mA), the most prevalent DNA modification in mammals and other eukaryotes, regulates DNA mismatch repair, chromosome replication, and transcription. However, its role in adult hippocampal neurogenesis remains unkown. Here we showed that the methyltransferase N6amt1 and 6 mA modification were highly enriched in hippocampal neurons both in vitro and in vivo. Functionally, knockdown of N6amt1 in neural stem cells (NSCs) significantly reduced 6 mA levels, neuronal genesis, and proliferation while promoting glial differentiation. Conversely, N6amt1 overexpression enhanced neuronal differentiation and proliferation. Mechanistically, N6amt1-mediated 6 mA modification of Txnrd3 DNA increased its transcription, thereby promoting hippocampal neurogenesis. Furthermore, exogenous Txnrd3 overexpression rescued the defects in cell differentiation and proliferation induced by N6amt1 depletion. Notably, N6amt1 deficiency impaired hippocampal neurogenesis and spatial memory in adult mice. Our findings highlight the critical role of DNA 6 mA in N6amt1-mediated neurogenesis and suggest that targeting N6amt1 may offer a novel therapeutic strategy for neurological disorders associated with cognitive impairment.