Chitale Shalaka, Richly Holger
Laboratory of Molecular Epigenetics, Institute of Molecular Biology, Mainz, Germany, Ackermannweg, Mainz, Germany.
Faculty of Biology, Johannes Gutenberg University, Mainz, Germany.
Oncotarget. 2017 May 9;8(19):30870-30887. doi: 10.18632/oncotarget.16142.
One of the major cellular DNA repair pathways is nucleotide excision repair (NER). It is the primary pathway for repair of various DNA lesions caused by exposure to ultraviolet (UV) light, such as cyclobutane pyrimidine dimers (CPDs) and 6-4 photoproducts. Although lesion-containing DNA associates with the nuclear matrix after UV irradiation it is still not understood how nuclear organization affects NER. Analyzing unscheduled DNA synthesis (UDS) indicates that NER preferentially occurs in specific nuclear areas, viz the nucleolus. Upon inducing localized damage, we observe migration of damaged DNA towards the nucleolus. Employing a LacR-based tethering system we demonstrate that H2A-ubiquitylation via the UV-RING1B complex localizes chromatin close to the nucleolus. We further show that the H2A-ubiquitin binding protein ZRF1 resides in the nucleolus, and that it anchors ubiquitylated chromatin along with XPC. Our data thus provide insight into the sub-nuclear organization of NER and reveal a novel role for histone H2A-ubiquitylation.
主要的细胞DNA修复途径之一是核苷酸切除修复（NER）。它是修复因暴露于紫外线（UV）而导致的各种DNA损伤的主要途径，如环丁烷嘧啶二聚体（CPD）和6-4光产物。尽管紫外线照射后含有损伤的DNA与核基质相关联，但核组织如何影响核苷酸切除修复仍不清楚。对非预定DNA合成（UDS）的分析表明，核苷酸切除修复优先发生在特定的核区域，即核仁。在诱导局部损伤后，我们观察到受损DNA向核仁迁移。利用基于LacR的拴系系统，我们证明通过UV-RING1B复合物进行的H2A泛素化使染色质定位在靠近核仁的位置。我们进一步表明，H2A泛素结合蛋白ZRF1存在于核仁中，并且它与XPC一起锚定泛素化染色质。因此，我们的数据为核苷酸切除修复的亚核组织提供了见解，并揭示了组蛋白H2A泛素化的新作用。
