Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, England, UK.
J Cell Biol. 2010 Dec 13;191(6):1061-8. doi: 10.1083/jcb.201006178. Epub 2010 Dec 6.
Chromatin structure is modulated during deoxyribonucleic acid excision repair, but how this is achieved is unclear. Loss of the yeast Ino80 chromatin-remodeling complex (Ino80-C) moderately sensitizes cells to ultraviolet (UV) light. In this paper, we show that INO80 acts in the same genetic pathway as nucleotide excision repair (NER) and that the Ino80-C contributes to efficient UV photoproduct removal in a region of high nucleosome occupancy. Moreover, Ino80 interacts with the early NER damage recognition complex Rad4-Rad23 and is recruited to chromatin by Rad4 in a UV damage-dependent manner. Using a modified chromatin immunoprecipitation assay, we find that chromatin disruption during UV lesion repair is normal, whereas the restoration of nucleosome structure is defective in ino80 mutant cells. Collectively, our work suggests that Ino80 is recruited to sites of UV lesion repair through interactions with the NER apparatus and is required for the restoration of chromatin structure after repair.
染色质结构在脱氧核糖核酸切除修复过程中被调节，但具体如何实现尚不清楚。酵母 Ino80 染色质重塑复合物（Ino80-C）的缺失会使细胞对紫外线（UV）光中度敏感。本文表明，INO80 与核苷酸切除修复（NER）处于相同的遗传途径中，Ino80-C 有助于在高核小体占有率区域有效去除 UV 光产物。此外，Ino80 与早期 NER 损伤识别复合物 Rad4-Rad23 相互作用，并通过 Rad4 在 UV 损伤依赖性方式被招募到染色质上。通过改良的染色质免疫沉淀分析，我们发现 UV 损伤修复过程中的染色质断裂是正常的，而在 ino80 突变细胞中核小体结构的恢复是有缺陷的。总的来说，我们的工作表明，Ino80 通过与 NER 装置的相互作用被招募到 UV 损伤修复部位，并在修复后恢复染色质结构中是必需的。
