Single-Molecule Visualization of Srs2-Mediated Rad51 Filament Disassembly During DNA Repair

Oyku Nefes Ozinanc

Abstract: In eukaryotic cells, replication protein A (RPA) binds rapidly to exposed single-stranded DNA (ssDNA) gaps to prevent secondary structure formation before passing the substrate to Rad51. Rad51 and replication protein A both play a role in maintaining genome stability during DNA replication. The balance between replication protein A displacement and Rad51 assembly is constantly scrutinized by the translocase Srs2. Srs2 plays a crucial role by translocating progressively from the 3? to the 5? end of the ssDNA, following the same orientation as Rad51 loading. We used single-molecule total internal reflection fluorescence (TIRF) microscopy to evaluate the fate of displaced Rad51 monomers during Srs2-mediated stripping. Rather than being released entirely into free solution, stripped Rad51 molecules are directly replaced by incoming replication protein A molecules tracking immediately behind the moving helicase. This coordinated translation prevents the exposure of naked single-stranded DNA, which protects the genomic template from endonucleolytic cleavage. Additionally, this single-molecule analysis reveals a cohesive, multi-protein recycling pathway that is important for maintaining single-stranded DNA homeostasis during active filament disassembly.

Keywords: Srs2, Rad51, Replication Protein A, Homologous Recombination, Single-Molecule Imaging, DNA Repair, TIRF Microscopy, Genome Stability

How to Cite?: Oyku Nefes Ozinanc, "Single-Molecule Visualization of Srs2-Mediated Rad51 Filament Disassembly During DNA Repair", Volume 15 Issue 6, June 2026, International Journal of Science and Research (IJSR), Pages: 1141-1143, https://www.ijsr.net/getabstract.php?paperid=SR26621105254, DOI: https://dx.doi.org/10.21275/SR26621105254

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