Non-linear DNA repair responses caused by interference between competitive repair pathways

电离辐射引起的DNA损伤是由各种碱基损伤组成的局部化损伤（簇状损伤）。预期损伤修复酶将在DNA上的局部区域受到干扰。在这项研究中，我们的目的是澄清酶过程的变化是否改变在集群损伤位点的酶活性。暴露于X射线的DNA样品用两种碱基切除修复酶，即Nth和Fpg处理。依次或同时加入酶。与我们最初的预期相反，改变酶处理的顺序并不影响酶的活性。该结果表明，即使在簇损伤位点中，每个基底损伤基本上分离，不会诱导每个酶途径之间的干扰。

Ionizing radiation induce localized DNA damage composed of various base lesions (clustered damage). It is expected that damage repair enzymes would be interfered at the localized area on DNA. In this study we aimed to clarify whether the variation of enzymatic processes modify each enzymatic activities at clustered damage site. DNA samples exposed to X-rays were treated with two base excision repair enzymes, namely Nth and Fpg. The enzymes were added sequentially or simultaneously. Contrast to our initial expectation, change of the order of the enzymatic treatments did not affect the activities of the enzymes. This result suggests that, even in a cluster damage site, each base lesions substantially separated not to induce interference between each enzymatic pathways.