Cldn7 is essential for in vitro gKO organoid survival and growth. (A) Representative bright-field images of in vitro organoid growth of PN3 WT and gKO SI crypts. Images were captured 1, 5, and 10 days after plating. (B) Comparison of organoid numbers on different days between WT and gKO SI crypts. n = 6; percentage of organoids were compared by 1-way analysis of variance, followed by the Dunnett multiple comparison test; ****P < .0001. Data are represented as means ± SEM. (C) Representative images of bright-field and whole-mount TUNEL staining from WT and gKO organoids after 10 days of culture (n = 3). (D) The 5-day WT and gKO organoids were double-stained with anti–claudin-7 antibody and Hoechst. (E) Enterocytes, EE cells, Paneth cells, and tuft cells were labeled by anti–FABP-1, anti–chromogranin A, antilysozyme, and anti–Dcamk-1 antibodies, respectively, on WT and gKO SI organoids after 5 days of culture. PCNA-positive proliferating cells were co-labeled with FABP-1. Arrowheads point to the corresponding cells labeled by specific antibodies. Images are representative of 3 independent experiments. (F) Goblet cells were stained by Alcian blue on WT and gKO SI organoids after a 5-day culture. Images are representative of 3 independent experiments. Scale bars: 100 μm.