Synergistic action of the Saccharomyces cereuisiae homologous recombination factors Rad54 and Rad51 in chromatin remodeling

Rad54, a member of the Swi2/Snf2 protein family, works in concert with the RecA-like recombinase Rad51 during the early and late stages of homologous recombination. Rad51 markedly enhances the activities of Rad54, including the induction of topological changes in DNA and the remodeling of chromatin structure. Reciprocally, Rad54 promotes Rad51-mediated DNA strand invasion with either naked or chromatinized DNA. Here, using various Saccharomyces cerevisiae rad51 and rad54 mutant proteins, mechanistic aspects of RadS4/Rad51-mediated chromatin remodeling are defined. Disruption of the RadS1-Rad54 complex leads to a marked attenuation of chromatin remodeling activity. Moreover, we present evidence that assembly of the Rad51 presynaptic filament represents an obligatory step in the enhancement of the chromatin remodeling reaction. Interestingly, we find a specific interaction of the N-terminal tail of histone H3 with Rad54 and show that the H3 tail interaction domain resides within the amino terminus of RadS4. These results suggest that Rad.54-mediated chromatin remodeling coincides with DNA homology search by the Rad51 presynaptic filament and that this process is facilitated by an interaction of Rad54 with histone H3. (C) 2007 Elsevier B.V. All rights reserved.