Article Dans Une Revue Molecular Cell Année : 2008

The Srs2 Helicase Activity Is Stimulated by Rad51 Filaments on dsDNA: Implications for Crossover Incidence during Mitotic Recombination

Résumé

Saccharomyces cerevisiae Srs2 helicase was shown to displace Rad51 in vitro upon translocation on single-stranded DNA. This activity is sufficient to account for its antirecombination effect and for the elimination of otherwise dead-end recombination intermediates. Roles for the helicase activity are yet unknown. Because cells lacking Srs2 show increased incidence of mitotic crossovers, it was postulated that Srs2 promotes synthesis-dependent strand annealing (SDSA) by unwinding the elongating invading strand from the donor strand. We report here that synthetic DNA structures that mimic D loops are good substrates for the Srs2 helicase activity, that Srs2 translocates on RPA-coated ssDNA, and, furthermore, that the helicase activity is largely stimulated by the presence of Rad51 nucleoprotein filaments on double-stranded DNA. These properties strongly support the idea that Srs2 actively prevents crossovers by promoting SDSA.

Dates et versions

hal-02990063 , version 1 (14-04-2023)

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Pauline Dupaigne, Cyrille Le Breton, Francis Fabre, Serge Gangloff, Eric Le Cam, et al.. The Srs2 Helicase Activity Is Stimulated by Rad51 Filaments on dsDNA: Implications for Crossover Incidence during Mitotic Recombination. Molecular Cell, 2008, 29 (2), pp.243-254. ⟨10.1016/j.molcel.2007.11.033⟩. ⟨hal-02990063⟩
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