TY - JOUR
T1 - On the mechanism of recombination hotspot scanning during double-stranded DNA break resection
AU - Carrasco, Carolina
AU - Gilhooly, Neville S
AU - Dillingham, Mark S
AU - Moreno-Herrero, Fernando
PY - 2013/6/24
Y1 - 2013/6/24
N2 - 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.
AB - 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.
U2 - 10.1073/pnas.1303035110
DO - 10.1073/pnas.1303035110
M3 - Article (Academic Journal)
C2 - 23798400
SN - 0027-8424
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
ER -