Fig. 7.

Microtubule polymerization regulates endoderm adhesion. (A-N) Embryos were exposed to DMSO (A-G) or nocodazole (H-N) during the stages prior to gut elongation (stage 35-41), and recovered in normal medium through stage 46. Compared with DMSO controls (A), nocodazole exposure perturbs gut elongation (H). Transverse sections were stained for β-catenin (red, cell-cell adhesion; B,E,I,L) and α-tubulin (green, MTs; C,F,J,M), with merged (red-green) images shown in D,G,K,N. Compared with the mature epithelium found lining the elongated gut tube of DMSO controls (B-G), epithelial morphogenesis is severely disrupted in the shortened guts induced by exposure to nocodazole (I-N). Endoderm cells are deficient in both MTs and β-catenin, and sort into inner (asterisks) and outer populations. Scale bars: 50 μm.