Abstract
The RecQ protein family, a group of highly conserved DNA helicases including Escherichia coli RecQ, Saccharomyces cerevisiae Sgs1, Shizosaccharomyces Rqh1 and five gene products in humans, plays important roles in maintaining genomic stability. A biochemical analysis showed that E. coli RecQ unwinds various short DNA substrates (19 bp) with a fork containing a gap on the leading strand more efficiently than those with a gap on the lagging strand. A genetic analysis showed that the recQ deletion suppresses the induction of SOS response and the cell filamentation in cells that carry the dnaE486 (a mutation in the DNA polymerase III α-catalytic subunit), causing high proportion of anucleated cells. These previous results suggest that RecQ functions to generate an initiating signal to recruit RecA for SOS induction at stalled replication forks, which are required for the cell cycle checkpoint. On the other hand, a recent report indicates that higher concentration of RecQ is required for unwinding long DNA than for the short DNA substrates as described above, suggesting that RecQ can unwind DNA from not only the end but also the middle of the DNA. In this study, we analyzed RecQ helicase activity using linearized plasmid DNA (2∼3 kb) with and without a fork to investigate DNA unwinding mechanism of RecQ in more detail and would like to discuss how RecQ rescues stalled replication forks.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
