Fig. 3.

Defects in cell cycle exit and lamellipodia formation in β-catenin mutant SCs in vivo and in vitro. (A–C) Proliferating SCs at P3, visualized by immunostainings using antibodies against proliferation marker Ki67. Dotted outlines surround axons. (Scale bar: 100 μm.) (D) Quantification of the proliferating cells. Shown is the percentage of the Ki67+ cells per nerve cross-section. (E–J) SC shape and lamellipodia formation were analyzed by immunostaining using antibodies against vinculin. SCs carrying β-catenin LOF mutations fail to produce terminal lamellipodia, whereas SCs mimicking β-catenin GOF mutations produce more lamellipodia. (Scale bars: 40 μm.) (K) Measurement of surface area of control, β-catenin LOF, and GOF SCc on laminin. Shown is the surface area quantified separately for cells containing zero to two, three to five, and more than five processes per cell. (L) Quantification of the number of terminal lamellipodia per cell in the β-catenin LOF and GOF cells, shown as fold changes, normalized to controls. (M–O) Lamellipodia formation in RT4 cells in the absence and presence of 40–200 ng/mL Wnt3a and 1 μg/μL Rspo3 ligands as assessed by immumostaining using Phalloidin (red) and antibodies against vinculin (green). (Scale bar: 40 μm.) (P) Quantification of lamellipodia in M–O. Error bars in D indicate SD (n = 3), and error bars in K, L, and P indicate SEM. t test: **P < 0.01.