Investigating Msh3 Mutations in Colorectal Cancer Within the African American Population and Their Impact on Genome Stability

Authors: Gorkem Bogubaev, Jennifer A. Surtees

SUNY Campus: SUNY Buffalo

Presentation Type: Poster

Location: Old Union Hall

Presentation #: 46

Timeslot: Session D 3:00-4:00 PM

Abstract: The mismatch repair (MMR) pathway plays a crucial role in maintaining genome integrity by correcting errors during DNA replication. In eukaryotic organisms, Msh2-Msh3 detects and directs repair of insertion/deletion loops. Mutations in MMR genes play a role in the development of colorectal cancer. Six distinct mutations in the human Msh3 gene have been identified within African American colorectal cancer patients, primarily in the ATPase and Msh2-Msh3 interaction regions, both critical for protein function. The conserved MMR pathway across eukaryotes make yeast an ideal model for studying MMR defects and their role in genomic instability and disease. The residues mutated in the colorectal cancer-associated mutations in human Msh3 align directly with those in yeast, and therefore we can create these analogous mutations in the yeast system. To understand the functional relevance of the Msh3 mutations, we will test the kinetics of wild-type and mutant human Msh2-Msh3 DNA-binding activity using Biolayer Interferometry (BLI). Site-directed mutagenesis will be used to introduce specific mutations for in vivo analysis in yeast. Mutator reporter assays will be performed to evaluate DNA slippage events, which result in insertion/deletion mutations if unrepaired. Additionally, we will evaluate the role of these msh3 alleles in 3′ non-homologous tail removal (3′ NHTR), a specialized double-strand break repair process requiring Msh2-Msh3 activity. This research will reveal the mechanistic and physiological effects of Msh3 mutations in the development of colorectal cancer in African American patients.