DNA single-strand break repair is impaired in aprataxin-related ataxia
DNA single-strand break repair is impaired in aprataxin-related ataxia
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DOI：
10.1002/ana.21078
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发表时间：
2007-02-01
影响因子：
11.2
通讯作者：
Ueno, Satoshi
中科院分区：
文献类型：
--
作者：
Hirano, Makito;Yamamoto, Aya;Ueno, Satoshi
目的：早发性共济失调伴眼运动性失用症和低白蛋白血症（EAOH）/共济失调伴眼运动性失用症I型（AOA 1）是一种常染色体隐性形式的小脑性共济失调。EAOH/AOA 1的致病蛋白Aprataxin（APTX）与X射线修复交叉互补1（XRCC 1）相互作用，XRCC 1是单链断裂（SSB）的支架DNA修复蛋白。本研究的目的是证明APTX在SSB修复（SSBR）的功能参与。方法：我们可视化的SSBR过程与最近开发的激光照射系统，允许实时观察SSBR蛋白质和局部紫外线照射系统，使用XPA-UVDE细胞系，修复DNA损伤完全通过SSBR。在细胞中使用小干扰RNA敲低APTX。氧化应激诱导的DNA损伤和细胞死亡进行了评估EAOH成纤维细胞和cerebellum.Results：我们的系统显示XRCC 1依赖的APTX招募SSB。SSBR在APTX敲低的细胞中受损。EAOH成纤维细胞中的氧化应激容易诱导SSB和细胞死亡，这被抗氧化剂阻断。EAOH cerebellum.Interpretation中证实了累积的氧化性DNA损伤：本研究提供了APTX在SSBR中的功能参与和EAOH/AOA 1中体内DNA损伤的第一个直接证据，并表明抗氧化剂治疗的益处。
Objective: Early-onset ataxia with ocular motor apraxia and hypoalbuminemia (EAOH)/ataxia with oculomotor apraxia type I (AOA1) is an autosomal recessive form of cerebellar ataxia. The causative protein for EAOH/AOA1, aprataxin (APTX), interacts with X-ray repair cross-complementing 1 (XRCC1), a scaffold DNA repair protein for single-strand breaks (SSBs). The goal of this study was to prove the functional involvement of APTX in SSB repair (SSBR).Methods: We visualized the SSBR process with a recently developed laser irradiation system that allows real-time observation of SSBR proteins and with a local ultraviolet-irradiation system using a XPA-UVDE cell line that repairs DNA lesions exclusively via SSBR. APTX was knocked down using small interference RNA in the cells. Oxidative stress-induced DNA damage and cell death were assessed in EAOH fibroblasts and cerebellum.Results: Our systems showed the XRCC1-dependent recruitment of APTX to SSBs. SSBR was impaired in APTX-knocked-down cells. Oxidative stress in EAOH fibroblasts readily induced SSBs and cell death, which were blocked by antioxidants. Accumulated oxidative DNA damage was confirmed in EAOH cerebellum.Interpretation: This study provides the first direct evidence for the functional involvement of APTX in SSBR and in vivo DNA damage in EAOH/AOA1, and suggests a benefit of antioxidant treatment.