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Updated: May 28, 2026

Detection of Homologous Recombination Intermediates via Proximity Ligation and Quantitative PCR in Saccharomyces cerevisiae
Published on: September 11, 2022
RecA homology search is promoted by mechanical stress along the scanned duplex DNA
Claudia Danilowicz1, Efraim Feinstein, Alyson Conover
1Department of Physics, Harvard University, Cambridge, MA 02138, USA.
Abstract:
A RecA-single-stranded DNA (RecA-ssDNA) filament searches a genome for sequence homology by rapidly binding and unbinding double-stranded DNA (dsDNA) until homology is found. We demonstrate that pulling on the opposite termini (3' and 5') of one of the two DNA strands in a dsDNA molecule stabilizes the normally unstable binding of that dsDNA to non-homologous RecA-ssDNA filaments, whereas pulling on the two 3', the two 5', or all four termini does not. We propose that the 'outgoing' strand in the dsDNA is extended by strong DNA-protein contacts, whereas the 'complementary' strand is extended by the tension on the base pairs that connect the 'complementary' strand to the 'outgoing' strand. The stress resulting from different levels of tension on its constitutive strands causes rapid dsDNA unbinding unless sufficient homology is present.
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