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Citation
Tags
HERO ID
7095001
Reference Type
Journal Article
Title
RecQ and RecG helicases have distinct roles in maintaining the stability of polypurine center dot polypyrimidine sequences
Author(s)
Dixon, BP; Lu, Lu; Chu, A; Bissler, JJ; ,
Year
2008
Is Peer Reviewed?
1
Journal
Mutation Research
ISSN:
0027-5107
EISSN:
1873-135X
Publisher
ELSEVIER SCIENCE BV
Location
AMSTERDAM
Page Numbers
20-28
PMID
18582477
DOI
10.1016/j.mrfmmm.2008.05.005
Web of Science Id
WOS:000259339600003
Abstract
DNA triplex structures can block the replication fork and result in double-stranded DNA breaks (DSBs). RecQ and RecG helicases may be important for replication of such sequences as RecQ resolves synthetic triplex DNA structures and RecG mediates replication restart by fork regression. Primer extension on an 88bp triplex-forming polypurine center dot polypyrimicline (Pu center dot Py) tract from the PKD1 gene demonstrated that RecQ, but not RecG, facilitated primer extension by T7 DNA polymerase. A high-throughput, dual plasmid screening system using isogenic bacterial lines deficient in RecG, RecQ, or both, revealed that RecQ deficiency increased mutation to sequence flanking this 88 bp tract by eight to ten-fold. Although RecG facilitated small deletions in an 88 bp mirror repeat-containing sequence, it was absolutely required to maintain a 2.5 kb Pu center dot Py tract containing multiple mirror repeats. These results support a two-tiered model where RecQ facilitates fork progression through triplex-forming tracts and, failing processivity, RecG is critical for replication fork restart. (c) 2008 Elsevier B.V. All rights reserved.
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