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Generation and Purification of Human INO80 Chromatin Remodeling Complexes and Subcomplexes
08:44

Generation and Purification of Human INO80 Chromatin Remodeling Complexes and Subcomplexes

Published on: October 23, 2014

The yeast high mobility group protein HMO2, a subunit of the chromatin-remodeling complex INO80, binds DNA ends

Sreerupa Ray1, Anne Grove

  • 1Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA.

Nucleic Acids Research
|September 4, 2009
PubMed

Insights

The Saccharomyces cerevisiae high mobility group protein (HMGB) HMO2 preferentially binds DNA ends and protects them from degradation. This suggests HMO2 plays a crucial role in DNA double-strand break (DSB) repair beyond its known function in the INO80 complex.

Area of Science:

  • Molecular Biology
  • Genetics
  • Biochemistry

Background:

  • DNA damage is a constant threat to cellular integrity.
  • The chromatin-remodeling complex INO80 is involved in DNA double-strand break (DSB) repair.
  • High mobility group proteins (HMGBs) are key players in DNA dynamics and repair.

Purpose of the Study:

  • To investigate the DNA-binding properties of Saccharomyces cerevisiae HMO2.
  • To determine HMO2's role in DNA end protection and DSB repair.
  • To elucidate HMO2's function beyond its association with the INO80 complex.

Main Methods:

  • DNA end-joining assays
  • Exonuclease protection assays
  • Binding affinity studies with varying DNA structures (blunt, cohesive, overhangs, supercoiled, linear, damaged DNA)

Main Results:

  • HMO2 exhibits preferential binding to DNA ends, with sequence-dependent recognition of single-stranded overhangs.
  • HMO2 protects DNA ends from exonucleolytic cleavage, requiring multiple protein molecules per end.
  • HMO2 binds supercoiled DNA more strongly than linear DNA and shows affinity for DNA with lesions like tandem mismatches.

Conclusions:

  • HMO2 possesses DNA end-binding and protective capabilities crucial for DNA repair.
  • The findings suggest a significant role for HMO2 in DSB repair, potentially independent of or in addition to its INO80 complex function.
  • HMO2's early recruitment to DSBs and protective functions highlight its importance in maintaining genomic stability.

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