Microtubule-associated protein 1b, a neuronal marker involved in odontoblast differentiation.
BACKGROUND
Map-1B belongs to the family of proteins that govern the dynamic state and organization of microtubules within cells. MAP-1B is a microtubule-associated protein highly expressed during the development of the nervous system. Its expression, regulated by the fragile X mental retardation protein (FMRP), is essential to stabilize microtubules during the elongation of dendrites and neurites. Other microtubules-associated molecules such as tau or MAP2 seem to act similarly. The aim of this work was to identify the MAP-1B expression in in vitro and in vivo human odontoblasts during development and carious processes. The expression of MAP2 and tau was also studied.


METHODS
In cultured cells, MAP-1B expression was analyzed by real-time polymerase chain reaction, flow cytometry, and Western blot. Its distribution was visualized by in situ hybridization and immunochemistry both in vitro and in vivo. The expression of FMRP, MAP2, and tau was identified by real-time polymerase chain reaction and immunochemistry.


RESULTS
MAP-1B is specifically expressed in odontoblasts from adult third molars as well as incisor germs from human embryos. In adult carious teeth, it is also expressed in newly differentiated dentin-forming cells. In vitro, MAP-1B expression is related to the differentiation state of odontoblasts. MAP-1B clearly underlines the cellular architecture of cell bodies and processes of differentiated cells. FMRP, MAP2, and tau are also detected in vivo.


CONCLUSIONS
On the basis of these data, MAP-1B could be considered as a new protein involved in the terminal differentiation of odontoblasts.
Maurin
Jean-Christophe
JC
University of Lyon, Lyon, France. jean-christophe.maurin@univ-reims.fr
Couble
Marie-Lise
ML
Staquet
Marie-Jeanne
MJ
Carrouel
Florence
F
About
Imad
I
Avila
Jesús
J
Magloire
Henry
H
Bleicher
Françoise
F
D000293:Adolescent; D000328:Adult; D015415:Biomarkers; D002454:Cell Differentiation; D002478:Cells, Cultured; D003731:Dental Caries / Q000378:metabolism*; D003782:Dental Pulp / Q000166:cytology / Q000378:metabolism*; D003809:Dentin, Secondary / Q000378:metabolism; D005333:Fetus; D051860:Fragile X Messenger Ribonucleoprotein 1 / Q000096:biosynthesis / Q000502:physiology; D006801:Humans; D007150:Immunohistochemistry; D008869:Microtubule-Associated Proteins / Q000096:biosynthesis*; D008964:Molar, Third / Q000166:cytology / Q000378:metabolism; D016501:Neurites / Q000378:metabolism; D009804:Odontoblasts / Q000166:cytology* / Q000378:metabolism*; D009805:Odontogenesis / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014083:Tooth Germ / Q000196:embryology / Q000378:metabolism; D014404:Tubulin / Q000096:biosynthesis; D016875:tau Proteins / Q000096:biosynthesis
D015415:Biomarkers; D051860:Fragile X Messenger Ribonucleoprotein 1; D008869:Microtubule-Associated Proteins; D014404:Tubulin; D016875:tau Proteins; C497683:FMR1 protein, human; C475491:MAP1B protein, human