Download A Novel Interacting Protein With The DNA Mismatch Repair Gene

51949
Colorectal Cancer Susceptibility Genes: A Novel Interacting Protein With The DNA
Mismatch Repair Gene PMS2
Jonathan Velasquez
Mentor: Steven Lipkin
DNA mismatch repair (MMR) is associated with hereditary non-polyposis colorectal cancer
(HNPCC), the most common known genetic cancer susceptibility syndrome. We are investigating
protein interactions between the DNA MMR protein PMS2 and Clone PMS2-Interactor 1 to explain
the dominant negative (DN) mechanism of DNA MMR failure. The N-terminus of PMS2 is known
to react with other proteins, and expression of the truncated N-terminus of PMS2 exhibits a
dominant negative phenotype and microsatellite instability (MSI). Mutated PMS2 does not inhibit
initial steps of MMR but interacts with and inhibits a downstream component of the MMR pathway.
We hypothesize that the clone construct interacts with and is inhibited by DN-mutated PMS2
resulting in increased levels of MSI and loss of DNA MMR function. We cloned Clone PMS2Interactor 1 through its interaction in the yeast two hybrid cloning assay with the N-terminus of
PMS2, and it is known to confer DN-MSI. Our initial study focused on Northern analysis of the 3’
untranslated mRNA of Clone PMS2-Interactor 1, demonstrating wide expression of PMS2Interactor 1 mRNA in mammalian tissues, predominantly in the testes and liver. We also focused on
expressing PMS2-Interactor 1 protein in bacteria and the development of reactive antisera for
Western analysis. Preliminary data and results show successful expression, and western analysis of the
antisera against the construct in bacteria demonstrates reactivity against both GST and PMS2Interactor 1. Our continued investigation using our developed antisera in immuno-precipitation
assays and western analysis with different mice tissue will characterize the tissues in which the protein
is expressed. Cell cultures with a PMS2-Interactor 1 and green fluorescent binding protein construct
will hopefully elucidate PMS2-Intercator 1 localization within cells.