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Updated: Aug 27, 2026

Real-time Observation of the DNA Strand Exchange Reaction Mediated by Rad51
Published on: February 13, 2019
Rad51 strand invasion function is needed for its role in CCTG tetranucleotide DNA repeat contractions
Symphony A Rutkowski1, Neila V Serumaga1, Eva J Bond1,2
1Biological Sciences, Cal State San Marcos, San Marcos, CA, United States.
Abstract:
Myotonic Dystrophy Type 2 is a genetic disorder caused by expanded CCTG DNA repeats in the CNBP gene. By using a genetic assay in Saccharomyces cerevisiae and knocking out RAD51 , we previously found that homologous recombination is involved in large-scale CCTG repeat contractions. In this study, we measured contraction rates using the RAD51-II3A allele, which is defective in homology search and strand invasion. We found that the mean contraction rate in the RAD51-II3A strain was indistinguishable from rad51Δ , indicating that structural properties alone of the repetitive CCTG sequence cannot initiate double strand break repair by promoting strand invasion.
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