Ku antigen interacts with abasic sites
Ku antigen interacts with abasic sites
复制标题
DOI：
10.1016/j.bbapap.2008.08.001
复制
发表时间：
2008-11-01
影响因子：
3.2
通讯作者：
Khodyreva, Svetlana N.
中科院分区：
文献类型：
--
作者：
Ilina, Ekaterina S.;Lavrik, Olga I.;Khodyreva, Svetlana N.
DNA中最丰富的病变之一是自发产生的基本位点（AP）或作为碱基切除修复的中间位点。参与这些病变处理的某些蛋白质与AP位点的脱氧核糖形成希夫碱。该中间体可通过NaBH4处理稳定。通过这种方法，利用带有AP位点的DNA双链来捕获细胞提取物中的蛋白质。在HeLa细胞提取物中，与普遍存在的表观分子质量为95 kDa的诱捕产物一起，观察到强度较小的低分子量产物。其中最主要的一个为Ku抗原（Ku）的p80亚基。Ku抗原是DNA依赖性蛋白激酶（DNA- pk）的DNA结合组分，参与双链断裂修复，并负责细胞对电离辐射的抗性。与非AP DNA相比，Ku与AP位点的特异性相互作用更有效地与类似的碱基DNA进行竞争。Ku80以不同的效率与AP dna交联，这取决于与AP位点相反的链中断的大小和位置。Ku抗原作为DNA-PK的一部分，被证明可以抑制无嘌呤/无嘧啶内切酶1对AP位点的切割。(C) 2008 Elsevier B.V.版权所有
One of the most abundant lesions in DNA is the abasic (AP) sites arising spontaneously or as an intermediate in base excision repair. Certain proteins participating in the processing of these lesions form a Schiff base with the deoxyribose of the AP site. This intermediate can be stabilized by NaBH4 treatment. By this method, DNA duplexes with AP sites were used to trap proteins in cell extracts. In HeLa cell extract, along with a prevalent trap product with an apparent molecular mass of 95 kDa, less intensive low-molecular-weight products were observed. The major one was identified as the p80-subunit of Ku antigen (Ku). Ku antigen, a DNA binding component of DNA-dependent protein kinase (DNA-PK), participates in double-stranded break repair and is responsible for the resistance of cells to ionizing radiation. The specificity of Ku interaction with AP sites was proven by more efficient competition of DNA duplexes with an analogue of abasic site than non-AP DNA. Ku80 was cross-linked to AP DNAs with different efficiencies depending on the size and position of strand interruptions opposite to AP sites. Ku antigen as a part of DNA-PK was shown to inhibit AP site cleavage by apurinic/apyrimidinic endonuclease 1. (C) 2008 Elsevier B.V. All rights reserved.