title: Dual origin of the epithelium of the mammalian middle ear.
abstract: The air-filled cavity and ossicles of the mammalian middle ear conduct sound to the cochlea. Using transgenic mice, we show that the mammalian middle ear develops through cavitation of a neural crest mass. These cells, which previously underwent an epithelial-to-mesenchymal transformation upon leaving the neural tube, undergo a mesenchymal-to-epithelial transformation to form a lining continuous with the endodermally derived auditory tube. The epithelium derived from endodermal cells, which surrounds the auditory tube and eardrum, develops cilia, whereas the neural crest-derived epithelium does not. Thus, the cilia critical to clearing pathogenic infections from the middle ear are distributed according to developmental derivations. A different process of cavitation appears evident in birds and reptiles, indicating that this dual epithelium may be unique to mammals.
authors.affiliation: Department of Craniofacial Development and Stem Cell Biology, King's College London, Guy's Hospital, London, UK, SE1 9RT.
authors.forename: Hannah
authors.initials: H
authors.lastname: Thompson
authors.forename: Abigail S
authors.initials: AS
authors.lastname: Tucker
mesh_terms: D000818:Animals; D002642:Chick Embryo; D002923:Cilia / Q000648:ultrastructure; D004432:Ear, Middle / Q000033:anatomy & histology / Q000166:cytology* / Q000196:embryology*; D047108:Embryonic Development; D004707:Endoderm / Q000166:cytology* / Q000196:embryology; D004847:Epithelial Cells / Q000648:ultrastructure; D058750:Epithelial-Mesenchymal Transition; D004848:Epithelium / Q000196:embryology* / Q000648:ultrastructure; D005260:Female; D008116:Lizards / Q000033:anatomy & histology / Q000196:embryology; D008297:Male; D008322:Mammals / Q000033:anatomy & histology / Q000196:embryology; D008648:Mesoderm / Q000196:embryology; D051379:Mice; D008822:Mice, Transgenic; D009432:Neural Crest / Q000166:cytology* / Q000196:embryology; D012788:Shrews / Q000033:anatomy & histology