Hereditary Nonpolyposis Colorectal Cancer (HNPCC) is an inherited disease that promotes the development of cancer. HNPCC patients are also at risk of developing other cancers throughout the body. HNPCC is linked to defects in the DNA mismatch repair mechanism (MMR). MMR corrects single point mutations resulted from unfaithful DNA replication. MutS Homolog 2 (MSH2) is one of the main MMR proteins necessary for identifying the point mutations. As a component of MMR, MSH2 works with the 3’-5’ exonuclease to correct DNA sequences that have been paired incorrectly. In this project, we investigated how sequence variations in MSH2 gene change the rate of mutation in yeast cells. Using molecular biology techniques and bioinformatic analysis, the mutation in MSH2 was identified as G704D. The mutated MSH2, wild-type MSH2, and the empty vector (pRS413) were introduced into yeast cells, then analyzed by FOA assay to measure the mutation rate in yeast. The data indicated that G704D mutation reduced the function of MSH2, which led to an increase in the overall mutation rate. The data obtained from our research project can be used to help researchers categorize the mutations in MSH2 into benign or defective mutations, which will facilitate early diagnosis of HNPCC.
