Deficient regulation of DNA double-strand break repair in Fanconi anemia fibroblasts
Deficient regulation of DNA double-strand break repair in Fanconi anemia fibroblasts
复制标题
DOI：
10.1074/jbc.m213251200
复制
发表时间：
2003-08-08
影响因子：
4.8
通讯作者：
Campbell, C
中科院分区：
文献类型：
--
作者：
Donahue, SL;Lundberg, R;Campbell, C
来自范可尼贫血（FA）患者的成纤维细胞显示基因组不稳定性、对DNA交联剂的超敏反应和DNA末端连接缺陷。未鉴定互补组的两名FA患者的成纤维细胞也具有显著增加的细胞同源重组（HR）活性。本文所述的结果显示，A、C和G组的患者来源的FA成纤维细胞中的HR活性水平是正常成纤维细胞中所见的HR活性水平的10倍。相反，D2组成纤维细胞的HR活性与正常细胞相同。Western印迹分析显示，在A、C和G组成纤维细胞中，RAD51蛋白升高至正常水平的10倍以上，但在D2组成纤维细胞中没有改变。在这些前细胞的HR活性水平可以恢复到接近正常水平的电穿孔与抗RAD51抗体，而类似的治疗正常和互补组D2成纤维细胞没有效果。这些发现与FA蛋白通过调节重组和非重组DNA修复来协调DNA双链断裂修复活性的模型是一致的。有趣的是，尽管DNA末端连接的正调控需要迄今为止测试的所有FA蛋白的组合存在，但最低程度地依赖于FANCA、FANCC和FANCG蛋白的HR抑制不需要FANCD 2。
Fibroblasts from patients with Fanconi anemia ( FA) display genomic instability, hypersensitivity to DNA cross-linking agents, and deficient DNA end joining. Fibroblasts from two FA patients of unidentified complementation group also had significantly increased cellular homologous recombination (HR) activity. Results described herein show that HR activity levels in patient-derived FA fibroblasts of groups A, C, and G were 10-fold greater than those seen in normal fibroblasts. In contrast, HR activity in group D2 fibroblasts was identical to that in normal cells. Western blot analysis revealed that the RAD51 protein was elevated 10-fold above normal levels in group A, C, and G fibroblasts, but was not altered in group D2 fibroblasts. HR activity levels in these former cells could be restored to near-normal levels by electroporation with anti-RAD51 antibody, whereas similar treatment of normal and complementation group D2 fibroblasts had no effect. These findings are consistent with a model in which FA proteins function to coordinate DNA double-strand break repair activity by regulating both recombinational and non-recombinational DNA repair. Interestingly, whereas positive regulation of DNA end joining requires the combined presence of all FA proteins thus far tested, suppression of HR, which is minimally dependent on the FANCA, FANCC, and FANCG proteins, does not require FANCD2.