Figure 2. CGN is required for the formation of a single apical lumen.

MDCK cells stably expressing CGN shRNA were embedded in 3D Matrigel and allowed to grow for 4 days (a–d) or 24 h (e–l) in the presence (dox+) or absence (dox−) of doxycycline. Cells were then fixed and stained with phalloidin-Alexa594 (a–c,e–h,k,l; red), anti-CGN (a–c and e–h; green), anti-tubulin (i,j; red) or anti-FIP5 (i,j; green) antibodies. Asterisks in (g,h,j) mark ectopic lumen formation sites. Arrows in (k) point to the AMIS. (d) shows quantification of cysts with one, two, or multiple lumens. Data shown are means and s.d. of three independent experiments. Consecutive images without an individual letter label show the same cell.