Homologous recombination (HR) helps maintain genome integrity, and HR defects give rise to disease, especially cancer. During HR, damaged DNA must be aligned with an undamaged template through a process referred to as the homology search. Despite decades of study, key aspects of this search remain undefined. Here, we use single-molecule imaging to demonstrate that Rad54, a conserved Snf2-like protein found in all eukaryotes, switches the search from the diffusion-based pathways characteristic of the basal HR machinery to an active process in which DNA sequences are aligned via an ATP-dependent molecular motor-driven mechanism. We further demonstrate that Rad54 disrupts the donor template strands, enabling the search to take place within a migrating DNA bubble-like structure that is bound by replication protein A (RPA). Our results reveal that Rad54, working together with RPA, fundamentally alters how DNA sequences are aligned during HR.

• PMID: 32502392
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Reference Type

Journal Article | Research Support, N.I.H., Extramural | Research Support, Non-U.S. Gov't

Authors

Crickard JB, Moevus CJ, Kwon Y, Sung P, Greene EC

Primary Lit For

RAD51 | RAD54 | Replication protein A complex

Additional Lit For

rad51-K191A | rad54-K341R

Review For