On the mechanism of recombination hotspot scanning during double-stranded DNA break resection

被引:30
作者
Carrasco, Carolina [1 ]
Gilhooly, Neville S. [2 ]
Dillingham, Mark S. [2 ]
Moreno-Herrero, Fernando [1 ]
机构
[1] CSIC, Ctr Nacl Biotecnol, Dept Macromol Struct, E-28049 Madrid, Spain
[2] Univ Bristol, Sch Biochem, Bristol BS8 1TD, Avon, England
基金
欧洲研究理事会; 英国生物技术与生命科学研究理事会;
关键词
protein motor; single molecule biophysics; DNA-end processing; real-time measurements; protein-DNA interactions; TRANSLOCATING RECBCD ENZYME; ADDAB HELICASE-NUCLEASE; CHI-RECOGNITION; HOMOLOGOUS RECOMBINATION; REGULATORY SEQUENCE; DYNAMIC DISORDER; SUPERCOILED DNA; REAL-TIME; MOLECULE; REVEALS;
D O I
10.1073/pnas.1303035110
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
Double-stranded DNA break repair by homologous recombination is initiated by resection of free DNA ends to produce a 3'-ssDNA overhang. In bacteria, this reaction is catalyzed by helicase-nuclease complexes such as AddAB in a manner regulated by specific recombination hotspot sequences called Crossover hotspot instigator (Chi). We have used magnetic tweezers to investigate the dynamics of AddAB translocation and hotspot scanning during double-stranded DNA break resection. AddAB was prone to stochastic pausing due to transient recognition of Chi-like sequences, unveiling an antagonistic relationship between DNA translocation and sequence-specific DNA recognition. Pauses at bona fide Chi sequences were longer, were nonexponentially distributed, and resulted in an altered velocity upon restart of translocation downstream of Chi. We propose a model for the recognition of Chi sequences to explain the origin of pausing during failed and successful hotspot recognition.
引用
收藏
页码:E2562 / E2571
页数:10
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