(A) Schematic of the Transwell apparatus containing a collagen scaffold, upon which human small intestinal monolayers are cultured. (B) Longitudinal cross section of monolayers stained with F-actin and Integrin β4 to label the luminal and basolateral regions, respectively. (C)
En face view of monolayers stained with F-actin and E-cadherin reveals characteristic flagstone staining pattern. Scale bar, 25 μm. (D) HSI monolayers consist primarily of proliferating, EdU+ cells. Colors used: EdU, red; DNA, blue.