Increased chromosome instability and accumulation of DNA double-strand breaks in Werner syndrome cells
Increased chromosome instability and accumulation of DNA double-strand breaks in Werner syndrome cells
复制标题
DOI：
10.1269/jrr.07017
复制
发表时间：
2007-05-01
影响因子：
2
通讯作者：
Kodama, Seiji
中科院分区：
文献类型：
--
作者：
Ariyoshi, Kentaro;Suzuki, Keiji;Kodama, Seiji
Werner综合征(WS)是由WRN基因突变引起的一种早衰综合征。在这里，我们证明了一株WS成纤维细胞显示出异常的核型，其特征是几个复杂的易位，当在类似的培养阶段检查时，异常中期包括无片段的双着丝粒染色体的频率是正常细胞的50倍。此外，端粒荧光原位杂交显示，WS细胞中出现异常信号、额外端粒信号和端粒信号丢失的频率是正常细胞的两到三倍。综上所述，这些结果表明，包括端粒维持功能障碍在内的染色体不稳定性在WS细胞中比在正常细胞中更为突出。此外，在WS细胞中，通过磷酸化ATM(共济失调性毛细血管扩张突变)灶检测到的G(1)期DNA双链断裂(DSB)，包括端粒DNA双链断裂(DSB)的积累，即使在低衰老水平也是加速的。在抗氧化剂的存在下，WS细胞中增加的DSB积累减少，这表明WS细胞中氧化应激的增强参与了DSB的加速积累。这些结果表明，由于WRN的缺陷，WS细胞容易自发积累DSB，导致染色体不稳定性增加，从而激活检查点，导致加速衰老。
Werner syndrome (WS) is a premature aging syndrome caused by mutations of the WRN gene. Here, we demonstrate that a strain of WS fibroblast cells shows abnormal karyotypes characterized by several complex translocations and 50-fold more frequency of abnormal metaphases including dicentric chromosomes without fragments than normal cells when examined at a similar culture stage. Further, telomere fluorescence in situ hybridization indicates that the abnormal signals, extra telomere signal and loss of telomere signal, emerge two- to three-fold more frequently in WS cells than in normal cells. Taken together, these results indicate that chromosome instability including dysfunction of telomere maintenance is more prominent in WS cells than in normal cells. In addition, the accumulation of DNA double-strand breaks (DSBs) at the G(1) phase, including those at telomeres, detected by phosphorylated ATM (ataxia telangiectasia mutated) foci is accelerated in WS cells even at a low senescence level. The increased accumulation of DSBs in WS cells is reduced in the presence of anti-oxidative agents, suggesting that enhanced oxidative stress in WS cells is involved in accelerated accumulation of DSBs. These results indicate that WS cells are prone to accumulate DSBs spontaneously due to a defect of WRN, which leads to increased chromosome instability that could activate checkpoints, resulting in accelerated senescence.