LAUSR

Recent studies have demonstrated that lysine acetylation of histones is crucial for nucleotide excision repair (NER) by relaxing the chromatin structure, which facilitates the recruitment of repair factors. However, few studies have focused on the contribution of histone deacetylases (HDAC) to NER. Here, we found that histone H3 Lys14 (H3K14) was deacetylated by HDAC3 after UV irradiation. Depletion of HDAC3 caused defects in cyclobutene pyrimidine dimer excision and sensitized cells to UV irradiation. HDAC3-depleted cells had impaired unscheduled DNA synthesis, but not recovery of RNA synthesis, which indicates that HDAC3 was required for global genome NER. Moreover, xeroderma pigmentosum, complementation group C (XPC) accumulation at the local UV-irradiated area was attenuated in HDAC3-depleted cells. In addition to the delay of XPC accumulation at DNA damage sites, XPC ubiquitylation was inhibited in HDAC3-depleted cells. These results suggest that the deacetylation of histone H3K14 by HDAC3 after UV irradiation contributes to XPC recruitment to DNA lesions to promote global genome NER. Implications: Involvement of histone deacetylation for XPC accumulation after UV irradiation indicates conversion of chromatin structure is essential for nucleotide excision repair in human cancer cells.