Abstract
Histone modifications can regulate many chromatin-related processes such as transcription, replication and DNA-repair, they can demarcate the genomic position of regulatory elements such as enhancers and may be involved in disease processes if misregulated. Despite a vast body of (mainly correlative) data arguing in favor of a central role of histone modifications for chromatin-dependent process (e.g. activation or repression of transcription), it is currently not clear to what extent histone modifications indeed functionally contribute (e.g. have a causative function) to the processes they are associated with. Our data now demonstrates a functional role of histone modifications in transcription and adds a new interesting twist to the debate on the functionality and causality of PTMs for the regulation of chromatin functions.