Histone modifications: crucial elements for damage response and chromatin restoration.

Eukaryotic genomes are packaged into chromatin from repeated nucleosome arrays in which DNA sequences wrap around histones. Chromatin organization has profound influence on DNA-templated processes such as transcription, DNA replication, and repair. Recent studies have also revealed chromatin dynamics as an active contributor to diverse DNA damage responses (DDR). Here, we review recent progress in histone modification related to DDR and post-repair chromatin restoration at the sites of DNA damage. We discuss how the timing and features of histone modifications would provide the initial as well as the final guidance for DDR, and the prospect that modifications may challenge the epigenetic stability of repaired cells and serve as damage memory in chromatin.