Coronal sections of control and MALSTKO mutant brains at E13.5 immunostained for MALS (A,B), PALS1 (C,D), Crb (E,F) and PATJ (G,H) reveal loss of MALS (B) and apical PATJ (H) relative to control. Coronal sections of control and MALSTKO mutant brains at E18.5 immunostained for aPKCζ (I, J), PALS1 (K,L), Crb (M,N) and PATJ (O,P) reveal loss of apical PALS1 (L) and PATJ (P) in MALSTKO mutants. Scale bar 10 μm. (Q) No changes were observed in total protein levels for any of the above proteins in MALSTKO mutant brains relative to control.