Loss of E-cad inhibited branching morphogenesis and induced epithelial disorganization in 3D culture. (A) E-cad^+/+;mT/mG and E-cad^fl/fl;mT/mG organoids were isolated, recombination was induced with Adeno-Cre, and branching morphogenesis was induced with FGF2. (B) E-cad⁺ organoids completed branching morphogenesis (Video 2). (C) E-cad⁻ organoids developed a disorganized basal surface composed of rounded cells (C’; Video 2). (D) This disorganized surface morphology was observed in 94% of E-cad⁻ organoids. n, number of time-lapse movies; r, number of biological replicates. (E and F) Basally positioned cells were green (Cre⁺), E-cad⁻ (E), and β-catenin⁻ (F). (G and H) In genetic mosaic organoids with a mixture of E-cad⁺ and E-cad⁻ cells, E-cad⁺ cells (red) were observed to initiate new buds (arrowheads; H’; Video 3). Bars: (B and C) 20 µm; (E, F, and H) 10 µm.