iTRAQ-based chromatin proteomic screen reveals CHD4-dependent recruitment of MBD2 to sites of DNA damage

Many DNA repair proteins can be recruited to DNA damage sites upon genotoxic stress. In order to search potential DNA repair proteins involved in cellular response to mitomycin C treatment, we utilized a quantitative proteome to uncover proteins that manifest differentially enrichment in the chromatin fraction after DNA damage. 397 proteins were identified, among which many factors were shown to be involved in chromatin modification and DNA repair by GO analysis. Specifically, methyl-CpG-binding domain protein 2 (MBD2) is revealed to be recruited to DNA damage sites after laser microirradiation, which was mediated through MBD domain and MBD2 C-terminus. Additionally, the recruitment of MBD2 is dependent on poly (ADP-ribose) and chromodomain helicase DNA-binding protein 4 (CHD4). Moreover, knockdown of MBD2 by CRISPR-Cas9 technique results in MMC sensitivity in mammalian cells.