CRB3 and Renal cyst: CRB3 knockout mice died shortly after birth and displayed epithelial morphogenesis defects such as cystic kidneys, proteinaceous debris throughout the lungs, villus fusion and apical membrane blebs in the intestines.4 Specifically, CRB3 repression disrupted tight junction (TJ) formation, while CRB3 increased the expression of the TJ proteins occludin and ZO-1.5, 6, 7, 8, 9, 10, 11