Fig. 1.

Apical defects in the adult Ez^−/− intestine. (A–D) Transmission EM of intestinal epithelia from tamoxifen-treated Ez^lox/lox (A and C) and Vil-Cre-ER^T2;Ez^lox/lox (B and D) mice. Control colonic (A) and small intestinal (C) epithelia maintain a highly organized BB featuring densely packed, uniform microvilli with actin rootlets embedded in a compact terminal web. Ez^−/− microvilli in colonic (B) and small intestinal epithelia (D) are nonuniform, misoriented, and extend from a thickened and disorganized terminal web; actin rootlets are disorganized or absent. (A and B) 2,900× magnification. (C and D) 11,000× magnification. (E and F) Large blebs of membrane no longer attached to the cytoskeleton are frequently found throughout the Ez^−/− intestine. (E) 15,000× magnification. (F) 7,100× magnification. (G and H) Phalloidin-stained colonic epithelia reveal the continuous apical band of actin labeling of the BB of control cells (G); actin is discontinuous in Ez^−/− cells (H). (G and H) 600× magnification.