Nonerythroid all spectrin is required for recruitment of FANCA and XPF to nuclear foci induced by DNA interstrand cross-links
Nonerythroid all spectrin is required for recruitment of FANCA and XPF to nuclear foci induced by DNA interstrand cross-links
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DOI：
10.1242/jcs.00294
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发表时间：
2003-03-01
影响因子：
4
通讯作者：
Lambert, MW
中科院分区：
文献类型：
--
作者：
Sridharan, D;Brown, M;Lambert, MW
哺乳动物细胞中负责修复DNA链间交联的事件、所涉及的蛋白质及其相互作用知之甚少。目前的研究表明，结构蛋白nonerythroid α血影蛋白（alphaSpIISigma*），存在于正常的人类细胞核中，在修复DNA链间交联中起着重要的作用。这些结果表明，在用DNA链间交联剂8-甲氧基补骨脂素加紫外线A（UVA）光损伤正常人细胞后，alphaSpIISigma* 重新定位于核灶，并且FANCA和已知的DNA修复蛋白XPF定位于相同的核灶。alphaSpIISigma* 对于这种重新定位是必不可少的，这通过以下发现来证明：在来自范可尼贫血互补A组（FA-A）患者的细胞中，其具有降低的修复DNA链间交联的能力和降低的alphaSpIISigma* 水平，损伤诱导的XPF以及alphaSpIISigma* 核灶的形成显著减少，即使XPF水平在这些细胞中是正常的。在校正的FA-A细胞中，其中alphaSpIISigma* 的水平恢复到正常，损伤诱导的核灶的数量也恢复到正常。免疫共沉淀研究表明，alphaSpIISigma*、FANCA和XPF与正常人核蛋白相互免疫共沉淀。这些结果表明，alphaSpIISigma*、FANCA和XPF在细胞核中相互作用，并表明这些蛋白质之间存在密切的功能关系。这些研究表明，alphaSpIISigma* 在细胞核中的一个重要作用是充当支架，帮助修复蛋白在损伤部位的募集和排列。
The events responsible for repair of DNA interstrand crosslinks in mammalian cells, the proteins involved and their interactions with each other are poorly understood. The present study demonstrates that the structural protein nonerythroid alpha spectrin (alphaSpIISigma*), present in normal human cell nuclei, plays an important role in repair of DNA interstrand cross-links. These results show that alphaSpIISigma* relocalizes to nuclear foci after damage of normal human cells with the DNA interstrand cross-linking agent 8-methoxypsoralen plus ultraviolet A (UVA) light and that FANCA and the known DNA repair protein XPF localize to the same nuclear foci. That alphaSpIISigma* is essential for this re-localization is demonstrated by the finding that in cells from patients with Fanconi anemia complementation group A (FA-A), which have decreased ability to repair DNA interstrand cross-links and decreased levels of alphaSpIISigma*, there is a significant reduction in formation of damage induced XPF as well as alphaSpIISigma* nuclear foci, even though levels of XPF are normal in these cells. In corrected FA-A cells, in which levels of alphaSpIISigma* are restored to normal, numbers of damage-induced nuclear foci are also returned to normal. Co-immunoprecipitation studies show that alphaSpIISigma*, FANCA and XPF co-immunoprecipitate with each other from normal human nuclear proteins. These results demonstrate that alphaSpIISigma*, FANCA and XPF interact with each other in the nucleus and indicate that there is a close functional relationship between these proteins. These studies suggest that an important role for alphaSpIISigma* in the nucleus is to act as a scaffold, aiding in recruitment and alignment of repair proteins at sites of damage.