KDM2B is a Histone H3K79 Demethylase and Induces Transcriptional Repression via SIRT1-mediated Chromatin Silencing. Homo sapiens

The methylation of histone H3 lysine 79 (H3K79) acts as an active chromatin marker and is enriched in actively transcribed regions of the genome. However, demethylase of this mark remains unknown despite intensive research. Here, we show that KDM2B (FBXL10), a member of the Jumonji C (JmjC) family of proteins and previously known for its histone H3K36 demethylase activity, is a di- and trimethyl H3K79 demethylase. We demonstrate that KDM2B induces transcriptional repression of HOXA7 and MEIS1 via occupancy of promoters and demethylation of H3K79. Furthermore, genome-wide analysis suggests that H3K79 methylation levels are increased when KDM2B is depleted, suggesting that KDM2B functions as an H3K79 demethylase in vivo. Finally, stable KDM2B-knockdown cell lines exhibited displacement of SIRT1, with concomitant increases in H3K79 methylation and H4K16 acetylation. Our findings identify KDM2B as an H3K79 demethylase and link its function to transcriptional repression via SIRT1-mediated chromatin silencing. Overall design: We profiled genomic occupancy of H3K79me2 and H3K79me3 via ChIP-seq for KDM2B KD and control in human 293T stable cell lines.