KtyII^−/− embryos show reduced and mislocalized desmoplakin, whereas adherens junctions and cell polarity are unaltered. (A and B) Double immunolabeling of keratin and desmoplakin (DP) on yolk sac indicates altered distribution and size of desmosomes in the presence (A) and absence (B) of keratins in yolk sac tissue. (C) Ninein part of the microtubule-organizing center complex at the centrosomes is located apically in WT (C) and KO embryonic intestine (C′). (D) Note the apical localization of occludin, a transmembrane protein of tight junctions. (E) Antibody staining of the tight junction marker ZO-1 in the yolk sac revealed no changes in WT (E) compared with KtyII^−/− (E′) E9.5 embryos. (D and E) ZO-1 and occludin are located at the apical plasma membrane of the yolk sac and the intestine, respectively, indicating normal cell polarity. (F) Intact adherens junctions in mutants (F′) and their WT littermates (F), as demonstrated by staining for E-cadherin (E-cad) in yolk sac tissues of E9.5 embryos. lu, lumen. Bars: (A–B″ and E–F′) 10 µm; (C–D′) 2 µm.