Histone H3K4 methylation keeps centromeres open for business

Eukaryotic centromeres are composed of a combination of nucleosomes containing the histone H3 variant CENP-A and canonical H3 di-methylated at lysine 4 (H3K4me2). Many questions exist over the functional importance of H3K4me2 nucleosomes within the centromere region. In this issue of The EMBO Journal, Bergmann et al (2011) reveal a role for H3K4me2 and transcription in CENP-A maintenance. They also extend the profile of centromeric histone modifications to include H3K36 methylation, typically found at transcribed regions of the genome.