Kinetic analysis of DNA double-strand break repair pathways in Arabidopsis
Kinetic analysis of DNA double-strand break repair pathways in Arabidopsis
复制标题
DOI：
10.1016/j.dnarep.2011.04.002
复制
发表时间：
2011-06-10
期刊：
影响因子：
3.8
通讯作者：
White, Charles I.
中科院分区：
文献类型：
--
作者：
Charbonnel, Cyril;Allain, Elisabeth;White, Charles I.
基因组DNA双链断裂（DSB）是一种潜在的致命损伤，它使染色体臂的一部分与着丝粒分离。通过重组修复DSB可以产生突变和进一步的染色体重排，因此重组的调控和重组途径的选择是最重要的。虽然重组机制的知识已经相当先进，但复杂的相互关系和调控途径还远未完全了解。我们通过对拟南芥突变体中γ - h2ax焦点出现和丢失的动力学定量分析了辐照植物G2/M期细胞核中DSB修复的不同途径。这些分析表明了四种主要重组途径在s期后DSB修复中的作用，非同源重组途径构成了主要的应答。这些数据表明，在这些细胞中DSB的修复存在层次结构：C-NHEJ先于B-NHEJ， B-NHEJ也可以抑制MMEJ。令人惊讶的是，ku80 xrcc1 xrcc2 xpf突变体可以修复DSB，尽管动力学发生了严重改变。这种修复导致大量的遗传不稳定，超过50%的有丝分裂在辐照后出现后期桥。本研究阐明了植物中DSB修复的不同途径之间的关系，并指出了新的DSB修复过程的存在。(C) 2011 Elsevier B.V.版权所有
Double-strand breaks in genomic DNA (DSB) are potentially lethal lesions which separate parts of chromosome arms from their centromeres. Repair of DSB by recombination can generate mutations and further chromosomal rearrangements, making the regulation of recombination and the choice of recombination pathways of the highest importance. Although knowledge of recombination mechanisms has considerably advanced, the complex interrelationships and regulation of pathways are far from being fully understood.We analyse the different pathways of DSB repair acting in G2/M phase nuclei of irradiated plants, through quantitation of the kinetics of appearance and loss of gamma-H2AX foci in Arabidopsis mutants. These analyses show the roles for the four major recombination pathways in post-S-phase DSB repair and that non-homologous recombination pathways constitute the major response. The data suggest a hierarchical organisation of DSB repair in these cells: C-NHEJ acts prior to B-NHEJ which can also inhibit MMEJ. Surprisingly the quadruple ku80 xrcc1 xrcc2 xpf mutant can repair DSB, although with severely altered kinetics. This repair leads to massive genetic instability with more than 50% of mitoses showing anaphase bridges following irradiation. This study thus clarifies the relationships between the different pathways of DSB repair in the living plant and points to the existence of novel DSB repair processes. (C) 2011 Elsevier B.V. All rights reserved.