FUT4 and inflammatory bowel disease: Glycosylation of the intestinal epithelium is a critical process that provides a potent source of nutrients for the microbiota and directly maintains the symbiotic relationship.42 Moreover, disruption or impaired epithelial glycosylation have been associated with the development of colorectal cancer and inflammatory bowel diseases.43–45 While Fut1 and Fut2 have been well characterized in the murine intestine to regulate fucosylation,46 we identified Fut4 and Fut8 as fructosyltransferases induced by microbiota in the crypt region (Supp table 1).