DOT1L-mediated CDK9 methylation is essential for DNA double-strand break repair

P-TEFb is a key regulator of transcription elongation and is composed of cyclin-dependent kinase 9 (CDK9) and cyclin T1. DOT1L is a histone H3K79 methyltransferase. Here, we show that treatment with the DOT1L inhibitor EPZ-5676 induces transcriptome changes in HCT116 cells. We further demonstrate that DOT1L methylates CDK9 at lysine 56 and that CDK9 methylation-deficient mutant K56A reshapes genome-wide CDK9 occupancy. Notably, changes in CDK9 occupancy are particularly pronounced at double-strand break (DSB)-related genes and are associated with the regulation of their transcription. This idataset includes RNA-seq and ChIP-seq data generated from HCT116 cells. Overall design: ChIP-seq were pereformed in CDK9-knockdown HCT116 cells reconstituted with either CDK9 WT or K56A mutant.