title: Expression patterns of Sema3F, PlexinA4, -A3, Neuropilin1 and -2 in the postnatal mouse molar suggest roles in tooth innervation and organogenesis.
abstract: OBJECTIVE
  Semaphorins form a family of axon wiring molecules but still little is known about their role in tooth formation. A class 3 semaphorin, Semaphorin3F (Sema3F), besides acting as a chemorepellant for different types of axons, controls a variety of non-neuronal developmental processes.
  
  
  METHODS
  Cellular mRNA expression patterns of Sema3F as well as neuropilin 1 (Npn1), neuropilin 2 (Npn2), plexinA3 and plexinA4 receptors were analyzed by sectional in situ hybridization in the mouse molar tooth during postnatal days 0-7. The expression of the receptors was studied in PN5 trigeminal ganglia.
  
  
  RESULTS
  Sema3F, Npn1, -2 and plexinA4 exhibited distinct, spatiotemporally changing expression patterns, whereas plexinA3 was not observed in the tooth germs. Besides being expressed in the base of the dental mesenchyme Sema3F, like plexinA4, Npn1 and -2, was present in the ameloblast cell lineage. Npn1 and Npn2 were additionally seen in the pulp horns and endothelial cells and like PlexinA4 in the developing alveolar bone. Npn1, plexinA3 and -A4 were observed in trigeminal ganglion neurons.
  
  
  CONCLUSIONS
  Sema3F may act as a tooth target-derived axonal chemorepellant controlling establishment of the tooth nerve supply. Furthermore, Sema3F, like Npn1, -2 and plexinA4 may serve non-neuronal functions by controlling the development of the ameloblast cell lineage. Moreover, Npn1 and Npn2 may regulate dental vasculogenesis and, together with PlexinA4, alveolar bone formation. Further analyses such as investigation of transgenic mouse models will be required to elucidate in vivo signaling functions of Sema3F and the receptors in odontogenesis.
authors.affiliation: Department of Biomedicine, University of Bergen, Bergen, Norway.
authors.forename: Angelina
authors.initials: A
authors.lastname: Sijaona
authors.forename: Keijo
authors.initials: K
authors.lastname: Luukko
authors.forename: Inger Hals
authors.initials: IH
authors.lastname: Kvinnsland
authors.forename: Päivi
authors.initials: P
authors.lastname: Kettunen
mesh_terms: D000565:Ameloblasts / Q000166:cytology; D000818:Animals; D002454:Cell Differentiation; D003782:Dental Pulp / Q000098:blood supply / Q000294:innervation* / Q000378:metabolism; D015870:Gene Expression; D017403:In Situ Hybridization; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology; D051379:Mice; D009419:Nerve Tissue Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D039942:Neuropilin-1 / Q000096:biosynthesis / Q000235:genetics; D039943:Neuropilin-2 / Q000096:biosynthesis / Q000235:genetics; D039921:Neuropilins / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D011956:Receptors, Cell Surface / Q000096:biosynthesis / Q000235:genetics; D039961:Semaphorins / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D014070:Tooth / Q000098:blood supply / Q000294:innervation* / Q000378:metabolism; D019228:Tooth Crown / Q000378:metabolism; D014083:Tooth Germ / Q000378:metabolism; D012668:Trigeminal Ganglion / Q000378:metabolism
chemical_list: D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D039943:Neuropilin-2; D039921:Neuropilins; C492110:Plxna4 protein, mouse; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; C491229:Sema3f protein, mouse; D039961:Semaphorins; D039942:Neuropilin-1