The KMT2F histone methyltransferase interacts with the RNA polymerase I machinery to promote ribosomal RNA transcription.

However, if and how this mark regulates RNA polymerase I (RNA Pol I) is not known. Here, we used customized genome assemblies for rDNA to demonstrate that KMT2A and KMT2F bind to entire rDNA loci.

The binding of these enzymes was mirrored by the binding of H3K4me2 and H3K4me3 marks. Using biochemical assays, we demonstrate the interaction of KMT2- specific subunits with RNA Pol I transcriptional machinery. Our findings reveal KMT2F as the primary KMT depositing the H3K4me3 on rDNA.