Role of IGFBPs in the morphogenesis of lingual papillae.
The expression of insulin-like growth factor binding proteins (IGFBPs) during the morphogenesis of lingual papillae of mice was examined by in situ hybridization. Among seven mouse IGFBPs, IGFBP-1, -6, and -7 mRNAs were not expressed in the tongue tissue. At E12, though no papillae have formed yet, IGFBP-2, -4, and -5 were expressed in the entire tongue epithelium. At E14, fungiform papillae appeared in the anterior region and circumvallate papillae were distinguished in the posterior region. Strong expression of IGFBP-5 was observed in the apical region of both fungiform and circumvallate papillae. At this stage, the epithelial elevation of filiform papillae was not clear; but IGFBP-5 was expressed in the apex. At E15, foliate papillae were distinguished and IGFBP-5 was expressed in the dorsal epithelium of ridges. In filiform papillae, IGFBP-3 was expressed in the core of the connective tissue. At E17, the expression of IGFBP-5 disappeared from the apical region of fungiform, filiform, foliate, and circumvallate papillae, whereas that of IGFBP-2 remained. This finding suggests that IGFBP-5 and -2 function to cause evagination of the epithelium into a raised structure. In the epithelium of trenches of foliate and circumvallate papillae, strong expression of IGFBP-4 was observed at E15 and E17. As previously suggested from a study on postnatal mice (Suzuki et al. J Comp Neurol 2005;482:74-84), IGFBP-4 acts in the epithelial invagination to form the trenches, grooves, or furrows of lingual papillae during development.
Suzuki
Yuko
Y
Department of Oral Anatomy, School of Dentistry, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Japan. suzuki@hoku-iryo-u.ac.jp
D000818:Animals; D003238:Connective Tissue / Q000196:embryology / Q000378:metabolism / Q000502:physiology; D004848:Epithelium / Q000196:embryology / Q000378:metabolism / Q000502:physiology; D005260:Female; D007150:Immunohistochemistry; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D018974:Insulin-Like Growth Factor Binding Protein 4 / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D018975:Insulin-Like Growth Factor Binding Protein 5 / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D018969:Insulin-Like Growth Factor Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008815:Mice, Inbred Strains; D009024:Morphogenesis; D011247:Pregnancy; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014059:Tongue / Q000196:embryology* / Q000378:metabolism / Q000502:physiology
D018971:Insulin-Like Growth Factor Binding Protein 2; D018972:Insulin-Like Growth Factor Binding Protein 3; D018974:Insulin-Like Growth Factor Binding Protein 4; D018975:Insulin-Like Growth Factor Binding Protein 5; D018969:Insulin-Like Growth Factor Binding Proteins; D012333:RNA, Messenger