Fig. 5. Epithelial cell adhesion and cytoplasmic organization are disrupted in jck^-/- kidneys. Light micrographs of kidney sections from two-week-old wild-type (A) and jck^-/- (B) mice from the kidney cortex. Tissue from jck mutants shows cyst formation in the connecting segments and cortical collecting ducts with evidence of cell detachment in the cyst lumens (arrowhead in B). Proximal tubules and glomeruli are not grossly affected in jck kidneys. Electron micrographs of wild type (C) and jck collecting ducts (D) reveal distension of the basal labyrinth in jck epithelia with large vacuolations (asterisk in D) and early signs of cell heightening and detachment (arrowhead in D) prior to overt cyst formation. Basal infoldings seen surrounding mitochondria in wild-type connecting segment cells (white arrowheads in E) are severely disrupted in jck connecting segments (arrowheads in F) and cellular organization is lost with large protrusions of cytoplasm extending into the forming cyst lumen (asterisk in F).