Abstract
Swi1 and Swi3 form the replication fork protection complex and play critical roles in proper activation of the replication checkpoint and stabilization of replication forks in the fission yeast Schizosaccharomyces pombe. However, the mechanisms by which the Swi1-Swi3 complex regulates these processes are not well understood. Here, we report functional analyses of the Swi1-Swi3 complex in fission yeast. Swi1 possesses the DDT domain, a putative DNA binding domain found in a variety of chromatin remodeling factors. Consistently, the DDT domain-containing region of Swi1 interacts with DNA in vitro, and mutations in the DDT domain eliminate the association of Swi1 with chromatin in S. pombe cells. DDT domain mutations also render cells highly sensitive to S-phase stressing agents and induce strong accumulation of Rad22-DNA repair foci, indicating that the DDT domain is involved in the activity of the Swi1-Swi3 complex. Interestingly, DDT domain mutations also abolish Swi1’s ability to interact with Swi3 in cells. Furthermore, we show that Swi1 is required for efficient chromatin association of Swi3 and that the Swi1 C-terminal domain directly interacts with Swi3. These results indicate that Swi1 associates with chromatin through its DDT domain and recruits Swi3 to function together as the replication fork protection complex.
Highlights
In response to replication stress, cells activate the DNA replication checkpoint to arrest the cell cycle and allow time for DNA repair
The Swi1-Swi3 replication fork protection complex was purified from E. coli cells co-expressing Swi1 and Swi3
The DDT domain contains about 60 amino acids with three alpha helices, and similar alpha helical composition is often found in various DNA binding domains of known structure [32]
Summary
In response to replication stress, cells activate the DNA replication checkpoint to arrest the cell cycle and allow time for DNA repair Central to this system are protein kinases such as human ATM and ATR, fission yeast Rad, and budding yeast Mec1 [1,2,3,4,5]. Recent studies found that ancillary factors, which are not essential for DNA synthesis but are important for DNA replication accuracy, travel with moving replication forks Such factors include fission yeast Swi and Swi, which together form the replication fork protection complex (FPC) and are required for efficient activation of the replication checkpoint kinase Cds and stabilization of stalled replication forks [12,13,14]. How the FPC protects replication forks and coordinates with multiple genome maintenance processes at the replication fork is not well understood
Sign-in/Register to view highlights & summary 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.
