Primary cilia of odontoblasts: possible role in molar morphogenesis.
A primary cilium, a sensory organelle present in almost every vertebrate cell, is regularly described in odontoblasts, projecting from the surfaces of the cells. Based on the hypothesis that the primary cilium is crucial both for dentin formation and possibly in tooth pain transmission, we have investigated the expression and localization of the main cilium components and involvement of the OFD1 gene in tooth morphogenesis. Odontoblasts in vitro express tubulin, inversin, rootletin, OFD1, BBS4, BBS6, ALMS1, KIF3A, PC1, and PC2. In vivo, cilia are aligned parallel to the dentin walls, with the top part oriented toward the pulp core. Close relationships between cilium and nerve fibers are evidenced. Calcium channels are concentrated in the vicinity of the basal body. Analysis of these data suggests a putative role of cilia in sensing the microenvironment, probably related to dentin secretion. This hypothesis is enhanced by the huge defects observed on molars from Ofd1 knockout mice, showing undifferentiated dentin-forming cells.
University of Lyon, Villeurbanne, F-69100, France.
B
B
Thivichon-Prince
M L
ML
Couble
A
A
Giamarchi
P
P
Delmas
B
B
Franco
L
L
Romio
T
T
Struys
I
I
Lambrichts
D
D
Ressnikoff
H
H
Magloire
F
F
Bleicher
D000293:Adolescent; D000818:Animals; D015220:Calcium Channels / Q000032:analysis / Q000648:ultrastructure; D018797:Cell Cycle Proteins; D002465:Cell Movement; D002478:Cells, Cultured; D002923:Cilia / Q000502:physiology*; D003598:Cytoskeletal Proteins / Q000032:analysis; D003782:Dental Pulp / Q000648:ultrastructure; D003804:Dentin / Q000648:ultrastructure; D056385:Group II Chaperonins; D006360:Heat-Shock Proteins / Q000032:analysis / Q000502:physiology*; D006801:Humans; D016547:Kinesins / Q000032:analysis; D051379:Mice; D018345:Mice, Knockout; D008869:Microtubule-Associated Proteins; D008963:Molar / Q000254:growth & development* / Q000648:ultrastructure; D018832:Molecular Chaperones / Q000032:analysis; D009024:Morphogenesis / Q000502:physiology; D009412:Nerve Fibers / Q000648:ultrastructure; D009804:Odontoblasts / Q000502:physiology*; D009805:Odontogenesis / Q000502:physiology*; D011506:Proteins / Q000032:analysis; D050396:TRPP Cation Channels / Q000032:analysis; D014157:Transcription Factors / Q000032:analysis; D014404:Tubulin / Q000032:analysis
D015220:Calcium Channels; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D056385:Group II Chaperonins; D006360:Heat-Shock Proteins; D016547:Kinesins; D008869:Microtubule-Associated Proteins; D018832:Molecular Chaperones; D011506:Proteins; D050396:TRPP Cation Channels; D014157:Transcription Factors; D014404:Tubulin; C490729:ALMS1 protein, human; C429655:BBS4 protein, human; C499237:CROCC protein, human; C114503:INVS protein, human; C087415:KIF3A protein, human; C414726:MKKS protein, human; C086058:ODF1 protein, human; C490109:Odf1 protein, mouse