| Budget Amount *help |
¥15,400,000 (Direct Cost: ¥15,400,000)
Fiscal Year 2006: ¥5,300,000 (Direct Cost: ¥5,300,000)
Fiscal Year 2005: ¥5,000,000 (Direct Cost: ¥5,000,000)
Fiscal Year 2004: ¥5,100,000 (Direct Cost: ¥5,100,000)
|
|---|
| Research Abstract |
To understand molecular mechanisms of recombination repair system in Schizosaccharomyces pombe, we analyzed "slr" mutants (synthetic lethal with rad2) and Swi5-Sfrl complex.
Project 1. Molecular analyses of slr mutant.
1-1. slr4^+is rad62^+ :
The slr^4+/rad62^+gene encodes one of a non-SMC subunits of SMC5-SMC6 proteins. It directly interacts with Smc5 subunits. Genetic analyses suggest that Rad62, in conjunction with SMC5/6, plays an essential role in recovery from stalled replication by recombination (ref. 1).
1-2. slr3^+ is mcl1^+ :
slr3^+/mcl1^+ is required for chromosome replication, cohesion and segregation. We suggest that Mcl1 is a functional S.cerevisiae Ctf4 homologue and plays in lagging-strand synthesis, in addtion to DNA repair (ref. 2).
1-3. slr5^+ is fbh1^+ :
slr.5^+/fbh1^+ encodes an F-box containing DNA helicase. We suggest that Fbh1 helicase is involved in processing in toxic intermediates formed during Rhp51-dependet recombination (ref. 3).
Project 2. Molecular analysis of Swi5-Sfr1 complex
Subnuclear localizations of Siw5 and Sfr1 and their mutual dependency suggest that-the Swi5/Sfr1 complex is a loading and/or stabilizing factor for the Rhp51 recombinase (ref. 5). There-strand exchange reaction assay using the purified protein components provides the robust evidence that Swi5-Sfr1 works as a recombination mediator. In addition, we demonstrated that it works as a mediator for Dmc1, a meiosis-specific recombinase (ref. 4). To reveal the functional differences between two mediators, we adopted an assay for repair products by an HO endonuclease-induced DSB. The result reveals that Rhp51 and Rhp57are essential, but Swi5/Sfr1 is not essential, for crossover production, indicating that two different mediator, Rhp55/57 and Swi5/Sfr1, process the DSB in different manner (ref. 5).
|
