A novel dual histone mark reader ZCWPW2 regulates meiotic recombination through lactylation and transcriptional regulation in humans and mice.

Meiotic recombination ensures accurate chromosome segregation and genetic diversity during gametogenesis, and its disruption leads to infertility. The dual histone methylation writer-reader system, in which PRDM9 deposits H3K4me3 and H3K36me3 marks at nucleosomes to define recombination hotspots and ZCWPW1 acts as a reader recognizing these marks, is essential for meiotic recombination. However, the regulatory mechanisms of this system remain unclear. Here, we showed that deficiency of ZCWPW2 causes recombination defects in humans and mice, including impaired homologous chromosome synapsis and defective DNA double-strand break repair. CUT&Tag analysis revealed that ZCWPW2 exhibits increased enrichment at dual H3K4me3 and H3K36me3 sites in the presence of PRDM9, while binding to promoter regions independently of PRDM9 to regulate meiotic transcription. Mass spectrometry further showed that ZCWPW2 forms a complex with ZCWPW1 and interacts with recombination-associated proteins in a ZCWPW1-dependent manner. Mechanistically, we demonstrate that the ZCWPW1-ZCWPW2 complex enhances the functions of key lactylation regulators LDHA and EP300, thereby promoting lactylation of recombination-associated proteins and stabilizing their abundance. Collectively, we identify ZCWPW2 as a previously unrecognized but essential factor in meiotic recombination, elucidate the molecular mechanism of the PRDM9/ZCWPW1/ZCWPW2 system in regulating recombination, and uncover a critical role for lactylation in meiosis.