Mucins are important molecules whose strategic position between the intestinal luminal contents and mucosal epithelial cells has suggested a number of important biological roles including the protection against adhesion by enteropathogens. Adhesion of bacteria to epithelial cells is crucial for subsequent toxin delivery, colonization and invasion. A number of studies have shown that mucin inhibits bacterial adhesion and evidence has suggested that the capacity of mucin to inhibit bacterial adhesion is altered in animal models of human diseases. Further analysis of the mucin molecule will be restrained by the limitations of proteins (apomucins) has been available through the application of cDNA cloning strategies which represent a significant advance in the field. Whereas longer sequences of the MUC2 intestinal mucin gene have been forthcoming the same is not true of the MUC3 intestinal mucin gene. A cell line has been induced to overexpress MUC3 mRNA and generation of a cDNA library will allow for cloning and sequencing the MUC3 mucin gene. With the alteration of the cell line to overexpress either MUC2 or MUC3 the role of distinct mucins in bacterial adhesion will be evaluated. This will be accomplished through both the comparison of direct adhesion to the cell subcultures and by purifying the different mucins for evaluation of mucins and their constituents in the process of inhibition of bacterial adhesion. The determination of bacterial adhesion to mucin constituents offers new and important strategies for which to facilitate bacterial clearance from the intestinal tract. Finally, animal homologues to intestinal mucin genes will be identified. The knowledge of these sequences in animals may have important consequences to our understanding of the biological significance of the various domains contained within human mucins. The studies will be performed at a major medical center under the research direction of a world leader in the molecular aspects of mucins. The candidate's proposed studies would be extension of studies completed to date using molecular techniques that will propel this research well into the future.