Related Experiment Videos
Human MSH2 binds to trinucleotide repeat DNA structures associated with neurodegenerative diseases
C E Pearson1, A Ewel, S Acharya
1Center for Genome Research, Institute of Biosciences and Technology in the Texas Medical Center, Texas A&M University, Houston 77030, USA. cpearson@ibt.tamu.edu
Human Molecular Genetics
|July 1, 1997
Summary
The human mismatch repair protein MSH2 binds specifically to DNA structures implicated in trinucleotide repeat expansion. This suggests MSH2 may play a role in neurodegenerative diseases caused by these expansions.
Area of Science:
- Molecular Biology
- Genetics
- Neuroscience
Background:
- Trinucleotide repeat expansion is linked to neurodegenerative diseases.
- The expansion mechanism may involve slipped-strand DNA structures.
Purpose of the Study:
- Investigate the interaction between human MSH2 and slipped-strand DNA structures.
- Determine the potential role of MSH2 in trinucleotide repeat expansion.
Main Methods:
- Examined genomic clones with (CTG)n x (CAG)n repeats.
- Constructed homoduplex (S-DNA) and heteroduplex (SI-DNA) slipped-strand structures.
- Utilized band-shift assays to study MSH2 binding.
Main Results:
- MSH2 binds to both S-DNA and SI-DNA in a structure-specific manner.
- MSH2 affinity increases with repeat sequence length.
- MSH2 preferentially binds to looped-out CAG repeats, indicating strand asymmetry.
Conclusions:
- MSH2 interaction with slipped-strand DNA is structure-dependent.
- MSH2 may be involved in trinucleotide repeat expansion through DNA repair or recombination pathways.