Hereditary Nonpolyposis Colorectal Cancer (HNPCC) or Lynch Syndrome is a genetic condition that is known to increase the risk of colon cancer. HNPCC accounts for about 5% of all colon cancer cases. HNPCC is caused by mutations in DNA mismatch-repair (MMR) genes such as MSH2. The MSH2 protein forms a heterodimer with other subunits such as MSH3 and MSH6 to perform MMR. This research aimed to test the effects of a single nucleotide polymorphism (SNP) in the MSH2 gene on MMR. Plasmid DNA from E. coli was extracted from cultures containing an empty vector (sp0), a wild type MSH2 gene (sp1), and a mutant msh2 gene (sp2). The identity of the plasmids were confirmed by restriction enzyme digestions, polymerase chain reaction (PCR), and gel electrophoresis. After aligning the wild type and mutant MSH2 protein sequences, the mutation was characterized as H658Y. This mutation is in a region that could potentially affect protein-protein interactions with other subunits that are necessary for MMR. Yeast were then transformed with the plasmid vectors and monitored for their growth and mutation rates. Methods from this project can be applied to other genetic disorders in an attempt to determine potential causes of other genetic diseases.
