Fig. 3

WNT4 promotes the correct localization of Paneth cells in the crypt. A, B 3D projections of mouse small intestinal organoids stained to visualize Paneth cells (lysozyme, green), F-actin (Phalloidin, red), and nuclei (Hoechst, blue). Organoids were transfected with si-control or si-Wnt4, or treated with an inhibitory Eph fragment (Eph, 10 μg/ml) in A, or transfected with Vector or Wnt4-OE in B. Scale bars, 25 μm. White arrows indicate Paneth cells positioned in the crypt base and yellow arrows indicate Paneth cells positioned away from the crypt base. C, D The frequency of Paneth cells distanced from the crypt base was quantified on the basis of the 3D projections of organoids in A and B. The tip of the organoid bud was identified as the crypt base. n = 79 Paneth cells for si-control, n = 98 Paneth cells for si-Wnt4, n = 101 Paneth cells for Eph, n = 54 Paneth cells for Vector, and n = 52 Paneth cells for Wnt4-OE