Gut microbiome of conventionally raised and germ-free Ern2-/- mice

Epithelial cells lining mucosal surfaces of the gastrointestinal and respiratory tracts uniquely express IRE1-beta (Ern2 gene), a paralogue of the most evolutionary conserved endoplasmic reticulum stress sensor IRE1-beta. How IRE1-beta functions at the host-environment interface, and why a second IRE1 paralogue evolved, remain incompletely understood. Using conventionally raised and germ-free Ern2-/- mice, we found that IRE1-beta was required for microbiota-induced goblet cell maturation and mucus barrier assembly in the colon. By regulating assembly of the colon mucus layer, IRE1-beta further shaped the composition of the gut microbiota. Mice lacking IRE1-beta had a dysbiotic microbial community that failed to induce goblet cell development when transferred into germ-free wild type mice.