In vitro role of Rad54 in Rad51 ssDNA filament dependent homology search and synaptic complexes formation
Homologous recombination (HR) uses a homologous template to accurately repair DNA double strand breaks and stalled replication forks to maintain genome stability. During homology search, Rad51 nucleoprotein filaments probe and interact with dsDNA, forming the synaptic complex that is stabilized on a homologous sequence. Strand intertwining leads to the formation of a displacement loop (D loop) In yeast, Rad54 is essential for HR in vivo and required for D loop formation in vitro, but its exact role remains to be fully elucidated. Using electron microscopy to visualize the DNA protein complexes, here we find that Rad54 is crucial for Rad51 mediated synaptic complex formation and homology search. The Rad54 K341R ATPase deficient mutant protein promotes formation of synaptic complexes but not D loops and leads to the accumulation of stable heterologous associations, suggesting that the Rad54 ATPase is involved in preventing non productive intermediates. We propose that Rad51/Rad54 form a functional unit operating in homology search, synaptic complex and D loop formation. Homologous recombination uses a template to accurately repair DNA double strand breaks and stalled replication forks to maintain genome stability. Here authors use electron microscopy to investigate the role of Rad54 in homology search and synaptic complex formation.
Nature Communications