title: Periderm cells covering palatal shelves have tight junctions and their desquamation reduces the polarity of palatal shelf epithelial cells in palatogenesis.
abstract: In palatogenesis, bilateral palatal shelves grow and fuse with each other to establish mesenchyme continuity across the horizontal palate. The palatal shelves are covered with the medial edge epithelium (MEE) in which most apical cells are periderm cells. We investigated localization and roles of tight junction (TJ) and adherens junction (AJ) components and an apical membrane marker in the MEE in palatogenesis. Immunofluorescence and immunoelectron microscopy analyses revealed that TJs were located at the boundary between neighboring periderm cells, whereas AJ components were localized at the boundary between all epithelial cells in the MEE. Specifically, typical AJs were observed at the boundaries between neighboring periderm cells and between periderm cells and underlying epithelial cells where the signal for nectin-1 was observed. The TGF-β-induced desquamation of periderm cells reduced the polarity of remaining epithelial cells as estimated by changes of epithelial cell morphology and the staining of the polarity marker and the AJ components. These less polarized epithelial cells then intermingled and finally disappeared at least partly by apoptosis. These results indicate that periderm cells covering growing palatal shelves have bona fide TJs and their desquamation reduces the polarity of palatal shelf epithelial cells in palatogenesis.
authors.affiliation: Division of Molecular and Cellular Biology, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan.
authors.forename: Midori
authors.initials: M
authors.lastname: Yoshida
authors.forename: Yohei
authors.initials: Y
authors.lastname: Shimono
authors.forename: Hideru
authors.initials: H
authors.lastname: Togashi
authors.forename: Kiyomi
authors.initials: K
authors.lastname: Matsuzaki
authors.forename: Jun
authors.initials: J
authors.lastname: Miyoshi
authors.forename: Akira
authors.initials: A
authors.lastname: Mizoguchi
authors.forename: Takahide
authors.initials: T
authors.lastname: Komori
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Takai
mesh_terms: D022005:Adherens Junctions / Q000378:metabolism; D000818:Animals; D017209:Apoptosis; D016764:Cell Polarity; D004622:Embryo, Mammalian / Q000166:cytology; D004847:Epithelial Cells / Q000378:metabolism*; D005260:Female; D006801:Humans; D051379:Mice; D038081:Organogenesis; D010159:Palate / Q000166:cytology* / Q000196:embryology* / Q000378:metabolism; D019108:Tight Junctions; D016212:Transforming Growth Factor beta / Q000378:metabolism
chemical_list: D016212:Transforming Growth Factor beta