Dengg Marlene, Garcia-Muse Tatiana, Gill Stephen G, Ashcroft Neville, Boulton Simon J, Nilsen Hilde
The Biotechnology Centre, University of Oslo, PO Box 1125 Blindern, Gaustadalleen 21, 0317 Oslo, Norway.
EMBO Rep. 2006 Oct;7(10):1046-51. doi: 10.1038/sj.embor.7400782. Epub 2006 Sep 8.
Incorporation of uracil during DNA synthesis is among the most common types of endogenously generated DNA damage. Depletion of Caenorhabditis elegans dUTPase by RNA interference allowed us to study the role of DNA damage response (DDR) pathways when responding to high levels of uracil in DNA. dUTPase depletion compromised development, caused embryonic lethality and led to activation of cell-cycle arrest and apoptosis. These phenotypes manifested as a result of processing misincorporated uracil by the uracil-DNA glycosylase UNG-1. Strikingly, abrogation of the clk-2 checkpoint gene rescued lethality and developmental defects, and eliminated cell-cycle arrest and apoptosis after dUTPase depletion. These data show a genetic interaction between UNG-1 and activation of the CLK-2 DDR pathway after uracil incorporation into DNA. Our results indicate that persistent repair intermediates and/or single-stranded DNA formed during repair of misincorporated uracil are tolerated in the absence of the CLK-2 checkpoint in C. elegans.
在DNA合成过程中尿嘧啶的掺入是内源性产生的DNA损伤的最常见类型之一。通过RNA干扰使秀丽隐杆线虫的dUTPase缺失，这使我们能够研究DNA损伤反应（DDR）途径在应对DNA中高水平尿嘧啶时的作用。dUTPase缺失会损害发育、导致胚胎致死，并导致细胞周期停滞和细胞凋亡的激活。这些表型是由尿嘧啶-DNA糖基化酶UNG-1处理错误掺入的尿嘧啶所致。引人注目的是，clk-2检查点基因的缺失挽救了致死性和发育缺陷，并消除了dUTPase缺失后的细胞周期停滞和细胞凋亡。这些数据表明在尿嘧啶掺入DNA后UNG-1与CLK-2 DDR途径的激活之间存在遗传相互作用。我们的结果表明，在秀丽隐杆线虫中缺乏CLK-2检查点的情况下，错误掺入的尿嘧啶修复过程中形成的持续修复中间体和/或单链DNA是可以耐受的。
