The tumor suppressor menin is a key scaffold mediator for homologous recombination repair.

SETD2-mediated H3K36me3 reprogramming is involved in homologous recombination (HR) repair; however, the dynamics of this repair process remain unclear. Here, we report that the scaffold protein menin, encoded by the Men1 gene, plays a crucial bridging role in H3K36-mediated HR repair. Genetic ablation of Men1 resulted in spontaneous lung carcinogenesis and was accompanied by severe genomic instability. Mechanistically, menin directly recognizes histone H2A.X via its Val371-Gln400 motif, and DNA damage markedly promotes the specific interaction between menin and γH2A.X. Subsequently, SETD2 is recruited to DNA damage sites by menin and acts as a writer to catalyze H3K36me3 reprogramming at local chromatin. LEDGF, as a reader, recognizes the H3K36me3 marker and further recruits CtIP as an effector to perform DNA end resection, ultimately activating the RPA2/Rad51 pathway. Restoring H3K36me3 via pharmacological intervention rescued impaired HR repair in Men1-deficient cells, further validating that menin governs HR repair in an H3K36me3-dependent manner. The results of the present study provide the detailed molecular mechanism underlying the previously described functions of H3K36me3 remodeling in HR repair.