New Insights in Chromosome Organization: Single Molecule Analysis of Eukaryotic SMC Complexes

Structural Maintenance of Chromosome (SMC) complexes, cohesin, condensin and Smc5/6, play a fundamental role in genome organization, facilitating chromosome compaction, segregation, and DNA repair. Despite their essential functions, the mechanisms by which the complexes interact with different DNA substrates and influence topological transitions remain not fully understood. Using the LUMICKS C-Trap, we have employed single-molecule approaches to analyze the behavior of purified SMC complexes, focusing on yeast cohesin and human SMC5/6, on different DNA substrates, including double-stranded (dsDNA) and single-stranded DNA (ssDNA). Additionally, we have used a quadrupole optical trap to bridging by SMC complexes and their effect on DNA decatenation by Topoisomerase IIα (Top2A). These findings provide new insights into the fundamental properties and requirements of cohesin and Smc5/6’s interaction with DNA substrates, as well as their ability to bridge two independent DNAs.

Key Learning Points:

• Explore the essential roles of SMC complexes like cohesin, condensin, and Smc5/6 in chromosome compaction, segregation, and DNA repair, and the latest development in understanding their mechanisms.
• Discover how the LUMICKS C-Trap is utilized to study the interactions of yeast cohesin and human Smc5/6 with both double-stranded and single-stranded DNA using advanced single-molecule approaches.
• Learn about the use of a quadrupole optical trap to explore the bridging capabilities of SMC complexes and their impact on DNA decatenation by Topoisomerase IIα (Top2A), providing new insights into their functional properties and requirements.