Thesis
Characterization of human MRE11 and MLH1 interacting domains, and the effects of pathogenic mutations on protein interaction
Washington State University
Master of Science (MS), Washington State University
2003
Handle:
https://hdl.handle.net/2376/115
Abstract
Hereditary Non-polyposis Colorectal Cancer (HNPCC) is largely attributed to mutations in human mismatch repair genes where currently, up to 55.6% of all incidences occur in hMLH1 gene. Our recent report on a direct protein interaction between hMLH1 and hMRE11 suggest that the interplay between these two proteins might play important roles in DNA mismatch repair and the pathogenesis of HNPCC. As an initial step to characterize the functionality of this protein interaction, we have determined the interacting domains of these two proteins. Specifically, the interacting domains were narrowed to C-terminal between amino acids 495-756 and 452-634 for hMLH1 and hMRE11 respectively. The hMRE11 interacting region is significantly overlapped with the interacting region for hPMS2. In addition, we have found that four out of seven HNPCC missense mutations (L574P, K618T, R659P, and A681T) showed a complete disruption of interaction, two mutations (Q542L and L582V) displayed partial defects, and one mutation (E578G) showed similar interaction to that of the hMLH1-hMRE11 wild type. This suggests the disruption of hMLH1-hMRE11 interaction could serve as an alternative molecular mechanism for the pathogenic effects of these mutations. Next, we have assessed the involvement of hMRE11 in the process of MMR. Evidences of hMRE11 as an essential requirement for human MMR process were examined by an in vitro partial reconstitution MMR assay. Addition of partially purified recombinant hMRE11 protein successfully repaired base mismatch in the 3'-5' direction. Thus this lends support that hMRE11 3'-5' exonuclease activity is involved in excising DNA fragment containing mismatch base.
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Details
- Title
- Characterization of human MRE11 and MLH1 interacting domains, and the effects of pathogenic mutations on protein interaction
- Creators
- Anthony Thien Vo
- Contributors
- Chengtao Her (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Molecular Biosciences, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525021201842
- Language
- English
- Resource Type
- Thesis