title: Distribution of keratin 8-containing cell clusters in mouse embryonic tongue: evidence for a prepattern for taste bud development.
abstract: The initiation of the morphogenesis of gustatory papillae is independent of innervation. To address the question of whether taste bud formation is associated with gustatory papilla morphogenesis, we examined developing tongues in mouse embryos from embryonic day 11 to birth. Despite the smooth morphological appearance of the lingual dorsal surface at 13 days of gestation, we observed embryonic taste bud primordia as discrete collections of cytokeratin 8-positive and elongated cells in epithelial placodes in the anterior tongue. In subsequent stages until birth, cytokeratin 8 continues to be expressed in embryonic taste buds distributed in punctuate patterns at regular intervals along rows that are symmetrically located on both sides of the median sulcus in the dorsal anterior developing tongue. Embryonic taste buds were observed in the developing circumvallate papillae from 15.5 days of gestation until birth. The dorsal epithelium of the anterior tongue is not innervated when embryonic taste buds first occur. The increased numbers of embryonic taste buds in developing fungiform papillae until birth are not correlated with the neural invasion of the epithelium. Thus, taste buds occur prenatally more likely independently of the innervation.
authors.affiliation: Department of Biomedical Sciences, Baylor College of Dentistry, The Texas A&M University System Health Science Center, Dallas, Texas 75246, USA. mbiene@tambcd.edu
authors.forename: Joseph-Pascal
authors.initials: JP
authors.lastname: Mbiene
authors.forename: John David
authors.initials: JD
authors.lastname: Roberts
mesh_terms: D000818:Animals; D002455:Cell Division; D005314:Embryonic and Fetal Development; D004847:Epithelial Cells / Q000166:cytology; D005260:Female; D005865:Gestational Age; D053533:Keratin-8; D007633:Keratins / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D009024:Morphogenesis; D011247:Pregnancy; D013650:Taste Buds / Q000196:embryology* / Q000648:ultrastructure; D014059:Tongue / Q000196:embryology* / Q000648:ultrastructure
chemical_list: D053533:Keratin-8; C486595:Krt8 protein, mouse; D007633:Keratins