A non-canonical role for the DNA glycosylase NEIL3 in suppressing APE1 endonuclease-mediated ssDNA damage
A non-canonical role for the DNA glycosylase NEIL3 in suppressing APE1 endonuclease-mediated ssDNA damage
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DOI：
10.1074/jbc.ra120.014228
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发表时间：
2020-10-09
影响因子：
4.8
通讯作者：
Yan, Shan
中科院分区：
文献类型：
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作者：
Ha, Anh;Lin, Yunfeng;Yan, Shan
DNA糖基化酶NEIL3通过其DNA糖基化酶和/或AP裂解酶活性参与DNA修复途径，包括碱基切除修复和链间交联修复途径，这被认为是NEIL3在基因组完整性中的典型作用。与其他DNA糖基酶NEIL1和NEIL2相比，非洲爪鼠neil3 C端含有两个高度保守的锌指基序，其中含有GRXF残基（称为Zf-GRF）。研究表明，次要的AP内切酶APE2只包含一个介导与单链DNA （ssDNA）相互作用的Zf-GRF基序，而主要的AP内切酶APE1则不包含。似乎两个NEIL3 Zf-GRF基序（称为Zf-GRF重复序列）对其DNA糖基化酶和AP裂解酶活性是必不可少的；然而，NEIL3 Zf-GRF重复序列在基因组完整性中的潜在功能仍然未知。在这里，我们证明了NEIL3 Zf-GRF重复序列与较短的ssDNA具有比单个Zf-GRF基序更高的亲和力。值得注意的是，我们的蛋白-蛋白相互作用分析显示，NEIL3 Zf-GRF重复序列与APE1相互作用，而不是与APE2相互作用。我们进一步发现，APE1在ssDNA上的内切酶活性受到NEIL3 Zf-GRF重复序列的损害，而在NEIL3中一个Zf-GRF基序不足以阻止APE1的这种活性。此外，COMET实验表明，在xenopusegg提取物中，过量的NEIL3 Zf-GRF重复可以减少氧化应激中的DNA损伤。总之，我们的研究结果表明，NEIL3通过其独特的Zf-GRF重复序列抑制APE1内切酶介导的ssDNA断裂，从而在基因组完整性中发挥非规范作用。
The DNA glycosylase NEIL3 has been implicated in DNA repair pathways including the base excision repair and the interstrand cross-link repair pathways via its DNA glycosylase and/or AP lyase activity, which are considered canonical roles of NEIL3 in genome integrity. Compared with the other DNA glycosylases NEIL1 and NEIL2,Xenopus laevisNEIL3 C terminus has two highly conserved zinc finger motifs containing GRXF residues (designated as Zf-GRF). It has been demonstrated that the minor AP endonuclease APE2 contains only one Zf-GRF motif mediating interaction with single-strand DNA (ssDNA), whereas the major AP endonuclease APE1 does not. It appears that the two NEIL3 Zf-GRF motifs (designated as Zf-GRF repeat) are dispensable for its DNA glycosylase and AP lyase activity; however, the potential function of the NEIL3 Zf-GRF repeat in genome integrity remains unknown. Here, we demonstrate evidence that the NEIL3 Zf-GRF repeat was associated with a higher affinity for shorter ssDNA than one single Zf-GRF motif. Notably, our protein-protein interaction assays show that the NEIL3 Zf-GRF repeat but not one Zf-GRF motif interacted with APE1 but not APE2. We further reveal that APE1 endonuclease activity on ssDNA but not on dsDNA is compromised by a NEIL3 Zf-GRF repeat, whereas one Zf-GRF motif within NEIL3 is not sufficient to prevent such activity of APE1. In addition, COMET assays show that excess NEIL3 Zf-GRF repeat reduces DNA damage in oxidative stress inXenopusegg extracts. Together, our results suggest a noncanonical role of NEIL3 in genome integrity via its distinct Zf-GRF repeat in suppressing APE1 endonuclease-mediated ssDNA breakage.