Tid1/Rdh54 promotes dissociation of Dmc1 from nonrecombinogenic sites on meiotic chromatin

Abstract

The meiosis-specific recombinase Dmc1 plays a critical role in DNA strand exchange in budding yeast. Tid1/Rdh54, a member of the Swi2/Snf2 family of DNA translocases, has been shown to stimulate Dmc1-dependent recombination. Tid1 and its budding yeast paralog Rad54 have a variety of biochemical activities that may contribute to their biological function. Here we demonstrate that Dmc1 can associate with chromatin in the absence of DNA double-strand breaks (DSBs), and Tid1 suppresses this association. Chromatin immunoprecipitation experiments indicate that an activity shared by Tid1 and Rad54 is required for normal assembly of Dmc1 at DSB sites in preparation for recombination. These results lead to a model in which the ATP hydrolysis-dependent DNA translocase activity of Tid1 acts to promote dissociation of Dmc1 from nonrecombinogenic sites on chromatin, with Rad54 being able to substitute for this function in the absence of Tid1. The tendency of Dmc1 to form unproductive interactions with chromatin is proposed to be a consequence of the mechanism of strand exchange. The results raise the possibility that ATP hydrolysis-dependent disruption of nonproductive recombinase-DNA interactions is a feature shared with other homologous recombination systems.

Characterization of the Interaction between the Saccharomyces cerevisiae Rad51 Recombinase and the DNA Translocase Rdh54

“…Similar to other members of the Swi2/Snf2 family of chromatin-remodeling proteins, Rdh54 possesses a DNA translocase activity that is fueled by ATP hydrolysis (21). The meiotic roles of Rdh54 are consistent with its ability to interact with Dmc1 and to translocate on DNA to prevent the accumulation of Dmc1 on chromatin, thus allowing its intracellular recycling for meiotic recombination processes (14). Moreover, Rdh54 promotes Dmc1-mediated DNA strand invasion (22).…”

“…Although its role in meiosis is not fully understood, Rdh54 is thought to promote colocalization of Rad51 and Dmc1 and to have a role in the dissolution of sister chromatid cohesion to facilitate appropriate interhomolog recombination and chromosome segregation (11)(12)(13). Importantly, the translocase function of Rdh54 acts to promote dissociation of Dmc1 from nonrecombinogenic sites on chromatin to allow Dmc1 to work in meiotic recombination (14). Recent studies suggest that Rdh54 has a similar role in preventing sequestration of Rad51 at non-DSB sites in mitotic cells.…”

Direct imaging of human Rad51 nucleoprotein dynamics on individual DNA molecules

“…Furthermore, because of its high affinity for dsDNA, in vivo observations confirm that Rad51 and its homologs associate with undamaged chromosomes to form dead-end complexes (42). In the case of the Rad51 homolog, Dmc1, these nonproductive chromosomal complexes are disassembled by Tid1, a Rad54 homolog (26,42,43). Disassembly of Rad51 nucleoprotein filaments occurs by association of Rad54 with the end of a nucleoprotein filament segment and suggests that Rad54 may target ADP-Rad51 nucleoprotein filaments (41); hence, the fact that Rad51-dsDNA filaments being relatively short and discontinuous both permits and promotes Rad54-mediated disassembly.…”

Regulation of Recombination and Genomic Maintenance

“…Both proteins form the active nucleoprotein filaments on ssDNA but also bind dsDNA with an affinity that is only slightly less than their ssDNA binding (see Morrical 2014;Brown and Bishop 2015). Thus, Rad51 and Dmc1 form dead-end complexes on duplex DNA, unless they are constantly dissociated by the motor proteins Rad54 and Rdh54/Tid1 (Solinger et al 2002;Holzen et al 2006;Shah et al 2010). Although such deadend complexes are not direct intermediates in the HR pathway, they illustrate the need for reversibility of DNA complexes formed by HR proteins.…”