DNA repair

Overview of the research

The genome of a cell is constantly damaged either as a results of normal  cellular processes or as external stimuli such as exposure to UV light or toxic chemicals. Proper repair of damages occurred in DNA is essential for proliferation of a cell. Among damage, double strand break (DSB) is known as the most deleterious and usually repaired by homologous recombination where damaged region is replaced to intact one by referring homologous sequence.  The proteins belong to RecA/Rad51 superfamily play critical role in the repair mechanism by forming a helical filament onto DNA. Therefore, the structural and mechanical properties of the RecA/Rad51-DNA filament is very important in understanding the repair mechanisms.

Techniques and results

Here we use the novel magnetic tweezers called FOMT and MTT to investigate the properties of the filament. Those techniques enable us to measure the twist and torque of a single molecule while retaining all the benefits of conventional magnetic tweezers. Using them, we were able to elucidate important aspects such as distortion of DNA occurred by binding of proteins and the alteration of the stability of the filament by the identity of cations , which have not been seen before.
fomt_rad51_v2
mtt_rad51_v2

Researchers currently involved in the project

  • Mina Lee
  • Jan Lipfert

Collaborations

  • Humberto Sanchez (Erasmus Medical Centre, Rotterdam)
  • Claire Wyman Lab (Erasmus Medical Centre, Rotterdam)

Publications specific to this project

M. Lee, J. Lipfert, H. Sanchez, C. Wyman, and N.H. Dekker
Structural and Torsional Properties of the RAD51-dsDNA Nucleoprotein Filament
Nucleic Acids Research 41, 7023–7030 (2013) [cover article]