title: Integrin subunit expression associated with epithelial-mesenchymal interactions during murine tooth development.
abstract: The initial information for patterning of early tooth development resides in the epithelium. Later, this is shifted to the mesenchyme. The process is governed by multiple epithelial-mesenchymal interactions. Integrins are cell surface receptors for extracellular matrix components. Expression of the beta 5 integrin subunit alternates between epithelium and mesenchyme during early tooth development (Yamada et al. [1994] Int. J. Dev. Biol. 38: 553-556). By immunofluorescence and in situ hybridization we show here a remarkably similar oscillating expression pattern of the alpha v integrin subunit. This subunit is known to associate with beta 5, and we therefore suggest that integrin alpha v beta 5 is involved in epithelial-mesenchymal interactions during tooth development. We also demonstrate that the developing tooth epithelium expresses the alpha 6, beta 1 and beta 4 subunits. The laminin receptors alpha 6 beta 1 and alpha 6 beta 4 may thus in part mediate the effect of basement membranes on tooth epithelial development. Interestingly, the enamel knot region expressed very little alpha 6 integrin subunit, whereas some expression was seen transiently in the condensing mesenchyme. During early tooth development, integrins possessing the alpha 6 subunit might also be involved in cell-cell interactions independently of laminins.
authors.affiliation: Department of Animal Physiology, Uppsala University, Sweden.
authors.forename: K
authors.initials: K
authors.lastname: Salmivirta
authors.forename: D
authors.initials: D
authors.lastname: Gullberg
authors.forename: E
authors.initials: E
authors.lastname: Hirsch
authors.forename: F
authors.initials: F
authors.lastname: Altruda
authors.forename: P
authors.initials: P
authors.lastname: Ekblom
mesh_terms: D000818:Animals; D002450:Cell Communication / Q000502:physiology*; D004847:Epithelial Cells; D004848:Epithelium / Q000378:metabolism; D016023:Integrins / Q000096:biosynthesis*; D008648:Mesoderm / Q000166:cytology / Q000378:metabolism; D051379:Mice; D009805:Odontogenesis / Q000502:physiology*; D015345:Oligonucleotide Probes; D012333:RNA, Messenger / Q000096:biosynthesis; D014083:Tooth Germ / Q000378:metabolism*
chemical_list: D016023:Integrins; D015345:Oligonucleotide Probes; D012333:RNA, Messenger