Motycka Teresa A, Bessho Tadayoshi, Post Sean M, Sung Patrick, Tomkinson Alan E
Molecular Medicine Graduate Program, Institute of Biotechnology, The University of Texas Health Science Center, San Antonio, Texas 78245, USA.
J Biol Chem. 2004 Apr 2;279(14):13634-9. doi: 10.1074/jbc.M313779200. Epub 2004 Jan 20.
The XPF/ERCC1 heterodimer is a DNA structure-specific endonuclease that participates in nucleotide excision repair and homology-dependent recombination reactions, including DNA single strand annealing and gene targeting. Here we show that XPF/ERCC1 is stably associated with hRad52, a recombinational repair protein, in human cell-free extracts and that these factors interact directly via the N-terminal domain of hRad52 and the XPF protein. Complex formation between hRad52 and XPF/ERCC1 concomitantly stimulates the DNA structure-specific endonuclease activity of XPF/ERCC1 and attenuates the DNA strand annealing activity of hRad52. Our results reveal a novel role for hRad52 as a subunit of a DNA structure-specific endonuclease and are congruent with evidence implicating both hRad52 and XPF/ERCC1 in a number of homologous recombination reactions. We propose that the ternary complex of hRad52 and XPF/ERCC1 is the active species that processes recombination intermediates generated during the repair of DNA double strand breaks and in homology-dependent gene targeting events.
XPF/ERCC1异二聚体是一种DNA结构特异性核酸内切酶，参与核苷酸切除修复和同源依赖性重组反应，包括DNA单链退火和基因靶向。我们在此表明，在人无细胞提取物中，XPF/ERCC1与重组修复蛋白hRad52稳定结合，并且这些因子通过hRad52的N端结构域和XPF蛋白直接相互作用。hRad52与XPF/ERCC1之间形成复合物会同时刺激XPF/ERCC1的DNA结构特异性核酸内切酶活性，并减弱hRad52的DNA链退火活性。我们的结果揭示了hRad52作为DNA结构特异性核酸内切酶亚基的新作用，并且与暗示hRad52和XPF/ERCC1参与多种同源重组反应的证据一致。我们提出，hRad52和XPF/ERCC1的三元复合物是处理DNA双链断裂修复过程中产生的重组中间体以及同源依赖性基因靶向事件中的活性物质。
