Title of Oral/Poster Presentation

Molecular basis for the physical interaction between the Rad51 recombinase and the SRS2 helicase.

Presenter Information

Matison RasmussenFollow

Class

Article

Department

Chemistry and Biochemistry

Faculty Mentor

Edwin Antony

Presentation Type

Poster Presentation

Abstract

Homologous recombination (HR) is a DNA repair mechanism that cells use to correct double stranded breaks in DNA. Defective HR leads to accumulation of DNA damage and uncontrolled HR leads to genomic instability and a variety of cancers. During HR, Rad51 forms a nucleoprotein filament on the DNA, both single stranded (ssDNA,) and double stranded (dsDNA.) Rad51 forms a somewhat transient bond with DNA, and the interaction is controlled by a number of mediators. It can be positively mediated, by proteins that promote continued binding, or can be removed by negative mediators. The Srs2 helicase is one such anti-HR mediator and functions by removing Rad51 from DNA. Our lab has discovered that Srs2 and Rad51 must physically interact for this anti-HR activity. Rad51 physically covers DNA during HR, therefore, every mediator protein has to interact with Rad51 to impose its regulatory activity. Given this interaction, my research goal is to uncover the interaction interface between Srs2 and Rad51, and role in mediating HR. Based on preliminary experiments, I hypothesize that this interaction interface lies at the surface of the Rad51 filament. I will test this hypothesis by generating specific mutations in Rad51 to disrupt the protein-protein interaction between Srs2 and Rad51. This work will uncover the structural and biochemical specifics of this interaction and its significance in mediating HR.

Start Date

4-9-2015 3:00 PM

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Apr 9th, 3:00 PM

Molecular basis for the physical interaction between the Rad51 recombinase and the SRS2 helicase.

Homologous recombination (HR) is a DNA repair mechanism that cells use to correct double stranded breaks in DNA. Defective HR leads to accumulation of DNA damage and uncontrolled HR leads to genomic instability and a variety of cancers. During HR, Rad51 forms a nucleoprotein filament on the DNA, both single stranded (ssDNA,) and double stranded (dsDNA.) Rad51 forms a somewhat transient bond with DNA, and the interaction is controlled by a number of mediators. It can be positively mediated, by proteins that promote continued binding, or can be removed by negative mediators. The Srs2 helicase is one such anti-HR mediator and functions by removing Rad51 from DNA. Our lab has discovered that Srs2 and Rad51 must physically interact for this anti-HR activity. Rad51 physically covers DNA during HR, therefore, every mediator protein has to interact with Rad51 to impose its regulatory activity. Given this interaction, my research goal is to uncover the interaction interface between Srs2 and Rad51, and role in mediating HR. Based on preliminary experiments, I hypothesize that this interaction interface lies at the surface of the Rad51 filament. I will test this hypothesis by generating specific mutations in Rad51 to disrupt the protein-protein interaction between Srs2 and Rad51. This work will uncover the structural and biochemical specifics of this interaction and its significance in mediating HR.