Stabilization of DNA fork junctions by Smc5/6 complexes revealed by single-molecule imaging

Tanasie, Nicoleta-Loredana; Gutiérrez-Escribano, Pilar; Jaklin, Sigrun; Aragon, Luis; Stigler, Johannes (2022): Stabilization of DNA fork junctions by Smc5/6 complexes revealed by single-molecule imaging. Cell Reports, 41 (10): 111778. ISSN 22111247

Abstract

SMC complexes play key roles in genome maintenance, where they ensure efficient genome replication and segregation. The SMC complex Smc5/6 is a crucial player in DNA replication and repair, yet many molecular features that determine its roles are unclear. Here, we use single-molecule microscopy to investigate Smc5/6’s interaction with DNA. We find that Smc5/6 forms oligomers that dynamically redistribute on dsDNA by 1D diffusion and statically bind to ssDNA. Using combined force manipulation and single-molecule microscopy, we generate ssDNA-dsDNA junctions that mimic structures present in DNA repair intermediates or replication forks. We show that Smc5/6 accumulates at these junction sites, stabilizes the fork, and promotes the retention of RPA. Our observations provide a model for the complex’s enrichment at sites of replication stress and DNA lesions from where it coordinates the recruitment and activation of downstream repair proteins.

• Doc-Type: Article (LMU)
• Organisational unit (Faculties): 18 Chemistry and Pharmacy > GeneCenter
• DFG subject classification of scientific disciplines: Natural sciences
• DFG: Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - 374605285
• DFG: Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - 491502892