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POSTER NO: 203 A protein-protein interaction map of the human MHC class III centromeric region
Ben Lehner, Stephanie E. Brown, R. Duncan Campbell, Christopher M. Sanderson Protein-protein interaction mapping allows the assignment of cellular functions to novel proteins and the integration of biochemical pathways at the cellular level. As a pilot study, we have used a stringent and high-throughput version of the yeast two-hybrid system to screen for protein-protein interactions using all the predicted intracellular proteins from a structural region of the human genome. The Major Histocompatiblity Complex Class III region has been independently linked to many autoimmune diseases, but because of the very high gene density and extensive linkage disequilibrium, fine-mapping is difficult. Assigning putative functions to genes by interaction mapping thus allows for the identification of candidate disease genes. The proteins screened include several well-studied proteins, as well as many novel ones, which allows the false-negative rate of the system to be estimated. To reduce the false-positive rate, the system uses 3 reporter constructs, each screen is replicated and each interaction is re-tested in fresh yeast cells by gap-repair recombination cloning. The specificity of each interaction is assessed by testing the interaction of each isolated protein with an irrelevant protein. The class III region gene-products represent many different protein domains, so the suitability of two-hybrid screening to different classes of human proteins can be assessed. Here we present the data for 14 proteins expressed from the centromeric end of the class III region: G18, PBX2, RNF5, DIR1, STK19, DOM3L, SKI2W, RD, NG36/G9A, LSM2, MSH5, DDAH2, VARS2 and G4. To our knowledge, this study represents the first systematic screen for protein-protein interactions using all the gene-products from a structural region of a mammalian genome. |