Cell and Tissue Research

, Volume 361, Issue 2, pp 457–466 | Cite as

Microtubule-associated protein tau (Mapt) is expressed in terminally differentiated odontoblasts and severely down-regulated in morphologically disturbed odontoblasts of Runx2 transgenic mice

  • Toshihiro Miyazaki
  • Tomomi T. Baba
  • Masako Mori
  • Takeshi Moriishi
  • Toshihisa Komori
Short Communication


Runx2 is an essential transcription factor for osteoblast and odontoblast differentiation and the terminal differentiation of chondrocytes. We have previously shown that the terminal differentiation of odontoblasts is inhibited in Runx2 transgenic {Tg(Col1a1-Runx2)} mice under the control of the 2.3-kb Col1a1 promoter, which directs the transgene expression to osteoblasts and odontoblasts. Odontoblasts show severe reductions in Dspp and nestin expression and lose their characteristic polarized morphology, including a long process extending to dentin, in Tg(Col1a1-Runx2) mice. We study the molecular mechanism of odontoblast morphogenesis by comparing gene expression in the molars of wild-type and Tg(Col1a1-Runx2) mice, focusing on cytoskeleton-related genes. Using microarray, we found that the gene expression of microtubule-associated protein tau (Mapt), a neuronal phosphoprotein with important roles in neuronal biology and microtubule dynamics and assembly, was high in wild-type molars but severely reduced in Tg(Col1a1-Runx2) molars. Immunohistochemical analysis revealed that Mapt was specifically expressed in terminally differentiated odontoblasts including their processes in wild-type molars but its expression was barely detectable in Tg(Col1a1-Runx2) molars. Double-staining of Mapt and Runx2 showed their reciprocal expression in odontoblasts. Mapt and tubulin co-localized in odontoblasts in wild-type molars. Immunoelectron microscopic analysis demonstrated Mapt lying around α-tubulin-positive filamentous structures in odontoblast processes. Thus, Mapt is a useful marker for terminally differentiated odontoblasts and might play an important role in odontoblast morphogenesis.


Microtubule-associated protein tau (Mapt) Odontoblast Cytoskeleton α-Tubulin Runx2 



We thank Y. Matsuo for technical assistance.

Supplementary material

441_2015_2135_MOESM1_ESM.pdf (72 kb)
Supplemental Table 1 (PDF 71 kb)
441_2015_2135_MOESM2_ESM.pdf (93 kb)
Supplemental Table 2 (PDF 92 kb)
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Supplemental Table 3 (PDF 85 kb)
441_2015_2135_MOESM4_ESM.pdf (718 kb)
Supplementary Figure 1 Hematoxylin and eosin (H-E) staining of a section of an extracted lower first molar at 2 weeks of age. Intercuspal and root regions indicated by boxes in a are magnified in b, c, respectively. No cellular degradation of the extracted teeth including periodontal tissues and reduced enamel epithelium (Re) is seen (D dentin, Dp dental pulp, Ob odontoblasts, Pl periodontal ligament). Bars 500 μm (a), 100 μm (b, c). (PDF 718 kb)
441_2015_2135_MOESM5_ESM.pdf (754 kb)
Supplementary Figure 2 Immunohistochemical analysis of Mapt. Localization of Mapt in frontal sections of the craniofacial region of wild-type (wt; a, c, d) and Tg(Col1a1-Runx2) (tg; b, e, f) mice at 1 day of age. Boxed regions in a, b are shown at higher magnification in c–f, respectively. Mapt expression (brown) is found in nervous tissues in both mice types, whereas it is located in odontoblasts in tooth germs of wild-type mice but not of Tg(Col1a1-Runx2) mice (arrows in c, e). Bars 1 mm (a, b), 100 μm (c–f). (PDF 754 kb)
441_2015_2135_MOESM6_ESM.pdf (734 kb)
Supplementary Figure 3 Immunohistochemical localization of DSP. Localization of DSP protein in the first molars in wild-type (wt, a, b, e, f) and Tg(Col1a1-Runx2) (tg) (c, d, g, h) mice at 1 day (a–d) and 9 days (e–h) of age. Boxed regions in a, c, e, g are shown at higher magnification in b, d, f, h, respectively. DSP expression is exclusively and strongly detected in differentiated odontoblasts, dentinal tubules and dentin matrices in wild-type mice, whereas it is faintly detected in odontoblasts in Tg(Col1a1-Runx2) mice (Ob odontoblasts). Bars 200 μm (a, c), 500 μm (e, g), 50 μm (b, d), 20 μm (f, h). (PDF 733 kb)
441_2015_2135_MOESM7_ESM.pdf (750 kb)
Supplementary Figure 4 Immunohistochemical localization of tubulin α1A. Localization of tubulin α1A protein in the first molars in wild-type (wt, a, b, e, f) and Tg(Col1a1-Runx2) (tg, c, d, g, h) mice at 1 day (a–d) and 9 days (e–h) of age. Boxed regions in a, c, e, g are shown at higher magnification in b, d, f, h, respectively. Tubulin α1A protein is detected in odontoblasts and in various other cells in both wild-type and Tg(Col1a1-Runx2) mice. The intensity of tubulin α1A staining was similar in odontoblasts of wild-type and Tg(Col1a1-Runx2) molars at 1 day of age, whereas it was reduced in odontoblasts of Tg(Col1a1-Runx2) molars at 9 days of age mainly because of the lack of the tall columnar cell body and polarization. Bars 200 μm (a, c), 500 μm (e, g), 50 μm (b, d), 20 μm (f, h). (PDF 750 kb)


  1. Aberg T, Wang XP, Kim JH, Yamashiro T, Bei M, Rice R, Ryoo HM, Thesleff I (2004) Runx2 mediates FGF signaling from epithelium to mesenchyme during tooth morphogenesis. Dev Biol 270:76–93. doi: 10.1016/j.ydbio.2004.02.012 PubMedCrossRefGoogle Scholar
  2. About I, Laurent-Maquin D, Lendahl U, Mitsiadis TA (2000) Nestin expression in embryonic and adult human teeth under normal and pathological conditions. Am J Pathol 157:287–295. doi: 10.1016/S0002-9440(10)64539-7 PubMedCentralPubMedCrossRefGoogle Scholar
  3. Al-Bassam J, Ozer RS, Safer D, Halpain S, Milligan RA (2002) MAP2 and tau bind longitudinally along the outer ridges of microtubule protofilaments. J Cell Biol 157:1187–1196. doi: 10.1083/jcb.200201048 PubMedCentralPubMedCrossRefGoogle Scholar
  4. Arana-Chavez VE, Massa LF (2004) Odontoblasts: the cells forming and maintaining dentine. Int J Biochem Cell Biol 36:1367–1373. doi: 10.1016/j.biocel.2004.01.006 PubMedCrossRefGoogle Scholar
  5. Baba TT, Ohara-Nemoto Y, Miyazaki T, Nemoto TK (2013) Involvement of geranylgeranylation of Rho and Rac GTPases in adipogenic and RANKL expression, which was inhibited by simvastatin. Cell Biochem Funct 31:652–659. doi: 10.1002/cbf.2951 PubMedCrossRefGoogle Scholar
  6. Begue-Kirn C, Krebsbach PH, Bartlett JD, Butler WT (1998) Dentin sialoprotein, dentin phosphoprotein, enamelysin and ameloblastin: tooth-specific molecules that are distinctively expressed during murine dental differentiation. Eur J Oral Sci 106:963–970PubMedCrossRefGoogle Scholar
  7. Black MM, Slaughter T, Moshiach S, Obrocka M, Fischer I (1996) Tau is enriched on dynamic microtubules in the distal region of growing axons. J Neurosci 16:3601–3619PubMedGoogle Scholar
  8. Bleicher F (2014) Odontoblast physiology. Exp Cell Res 325:65–71. doi: 10.1016/j.yexcr.2013.12.012 PubMedCrossRefGoogle Scholar
  9. Bleicher F, Couble ML, Buchaille R, Farges JC, Magloire H (2001) New genes involved in odontoblast differentiation. Adv Dent Res 15:30–33PubMedCrossRefGoogle Scholar
  10. Bronckers AL, Engelse MA, Cavender A, Gaikwad J, D’Souza RN (2001) Cell-specific patterns of Cbfa1 mRNA and protein expression in postnatal murine dental tissues. Mech Dev 101:255–258PubMedCrossRefGoogle Scholar
  11. Buchaille R, Couble ML, Magloire H, Bleicher F (2000) A substractive PCR-based cDNA library from human odontoblast cells: identification of novel genes expressed in tooth forming cells. Matrix Biol 19:421–430PubMedCrossRefGoogle Scholar
  12. Caceres A, Kosik KS (1990) Inhibition of neurite polarity by tau antisense oligonucleotides in primary cerebellar neurons. Nature 343:461–463. doi: 10.1038/343461a0 PubMedCrossRefGoogle Scholar
  13. Carda C, Peydro A (2006) Ultrastructural patterns of human dentinal tubules, odontoblasts processes and nerve fibres. Tissue Cell 38:141–150. doi: 10.1016/j.tice.2006.01.002 PubMedCrossRefGoogle Scholar
  14. Chen J, Kanai Y, Cowan NJ, Hirokawa N (1992) Projection domains of MAP2 and tau determine spacings between microtubules in dendrites and axons. Nature 360:674–677. doi: 10.1038/360674a0 PubMedCrossRefGoogle Scholar
  15. Chen S, Rani S, Wu Y, Unterbrink A, Gu TT, Gluhak-Heinrich J, Chuang HH, Macdougall M (2005) Differential regulation of dentin sialophosphoprotein expression by Runx2 during odontoblast cytodifferentiation. J Biol Chem 280:29717–29727. doi: 10.1074/jbc.M502929200 PubMedCrossRefGoogle Scholar
  16. D’Souza RN, Aberg T, Gaikwad J, Cavender A, Owen M, Karsenty G, Thesleff I (1999) Cbfa1 is required for epithelial-mesenchymal interactions regulating tooth development in mice. Development 126:2911–2920PubMedGoogle Scholar
  17. Dehmelt L, Halpain S (2005) The MAP2/Tau family of microtubule-associated proteins. Genome Biol 6:204. doi: 10.1186/gb-2004-6-1-204 PubMedCentralPubMedCrossRefGoogle Scholar
  18. DiTella MC, Feiguin F, Carri N, Kosik KS, Caceres A (1996) MAP-1B/TAU functional redundancy during laminin-enhanced axonal growth. J Cell Sci 109:467–477PubMedGoogle Scholar
  19. Drewes G, Ebneth A, Mandelkow EM (1998) MAPs, MARKs and microtubule dynamics. Trends Biochem Sci 23:307–311PubMedCrossRefGoogle Scholar
  20. Feinstein SC, Wilson L (2005) Inability of tau to properly regulate neuronal microtubule dynamics: a loss-of-function mechanism by which tau might mediate neuronal cell death. Biochim Biophys Acta 1739:268–279. doi: 10.1016/j.bbadis.2004.07.002 PubMedCrossRefGoogle Scholar
  21. Garant PR (1972) The organization of microtubules within rat odontoblast processes revealed by perfusion fixation with glutaraldehyde. Arch Oral Biol 17:1047–1058PubMedCrossRefGoogle Scholar
  22. Goldberg M, Smith AJ (2004) Cells and extracellular matrices of dentin and pulp: a biological basis for repair and tissue engineering. Crit Rev Oral Biol Med 15:13–27PubMedCrossRefGoogle Scholar
  23. Hall GF (2012) The biology and pathobiology of tau protein. In: Kavallaris M (ed) Cytoskeleton and human disease. Humana/Springer, New York, pp 285–313CrossRefGoogle Scholar
  24. Harada A, Oguchi K, Okabe S, Kuno J, Terada S, Ohshima T, Sato-Yoshitake R, Takei Y, Noda T, Hirokawa N (1994) Altered microtubule organization in small-calibre axons of mice lacking tau protein. Nature 369:488–491. doi: 10.1038/369488a0 PubMedCrossRefGoogle Scholar
  25. Hirokawa N, Shiomura Y, Okabe S (1988) Tau proteins: the molecular structure and mode of binding on microtubules. J Cell Biol 107:1449–1459PubMedCrossRefGoogle Scholar
  26. Huang W da, Sherman BT, Lempicki RA (2009) Systematic and integrative analysis of large gene lists using DAVID bioinformatics resources. Nat Protoc 4:44–57. doi: 10.1038/nprot.2008.211
  27. Iqbal K, Alonso Adel C, Chen S, Chohan MO, El-Akkad E, Gong CX, Khatoon S, Li B, Liu F, Rahman A, Tanimukai H, Grundke-Iqbal I (2005) Tau pathology in Alzheimer disease and other tauopathies. Biochim Biophys Acta 1739:198–210. doi: 10.1016/j.bbadis.2004.09.008 PubMedCrossRefGoogle Scholar
  28. Kawagishi E, Nakakura-Ohshima K, Nomura S, Ohshima H (2006) Pulpal responses to cavity preparation in aged rat molars. Cell Tissue Res 326:111–122. doi: 10.1007/s00441-006-0230-4 PubMedCrossRefGoogle Scholar
  29. Kempf M, Clement A, Faissner A, Lee G, Brandt R (1996) Tau binds to the distal axon early in development of polarity in a microtubule- and microfilament-dependent manner. J Neurosci 16:5583–5592PubMedGoogle Scholar
  30. Knops J, Kosik KS, Lee G, Pardee JD, Cohen-Gould L, McConlogue L (1991) Overexpression of tau in a nonneuronal cell induces long cellular processes. J Cell Biol 114:725–733PubMedCrossRefGoogle Scholar
  31. Kobayashi N, Mundel P (1998) A role of microtubules during the formation of cell processes in neuronal and non-neuronal cells. Cell Tissue Res 291:163–174PubMedCrossRefGoogle Scholar
  32. Komori T (2010) Regulation of bone development and extracellular matrix protein genes by RUNX2. Cell Tissue Res 339:189–195. doi: 10.1007/s00441-009-0832-8 PubMedCrossRefGoogle Scholar
  33. Komori T, Yagi H, Nomura S, Yamaguchi A, Sasaki K, Deguchi K, Shimizu Y, Bronson RT, Gao YH, Inada M, Sato M, Okamoto R, Kitamura Y, Yoshiki S, Kishimoto T (1997) Targeted disruption of Cbfa1 results in a complete lack of bone formation owing to maturational arrest of osteoblasts. Cell 89:755–764PubMedCrossRefGoogle Scholar
  34. Lee Y, Go EJ, Jung HS, Kim E, Jung IY, Lee SJ (2012) Immunohistochemical analysis of pulpal regeneration by nestin expression in replanted teeth. Int Endod J 45:652–659. doi: 10.1111/j.1365-2591.2012.02024.x PubMedCrossRefGoogle Scholar
  35. Li S, Kong H, Yao N, Yu Q, Wang P, Lin Y, Wang J, Kuang R, Zhao X, Xu J, Zhu Q, Ni L (2011) The role of runt-related transcription factor 2 (Runx2) in the late stage of odontoblast differentiation and dentin formation. Biochem Biophys Res Commun 410:698–704. doi: 10.1016/j.bbrc.2011.06.065 PubMedCrossRefGoogle Scholar
  36. Linde A, Goldberg M (1993) Dentinogenesis. Crit Rev Oral Biol Med 4:679–728PubMedGoogle Scholar
  37. Liu W, Toyosawa S, Furuichi T, Kanatani N, Yoshida C, Liu Y, Himeno M, Narai S, Yamaguchi A, Komori T (2001) Overexpression of Cbfa1 in osteoblasts inhibits osteoblast maturation and causes osteopenia with multiple fractures. J Cell Biol 155:157–166. doi: 10.1083/jcb.200105052 PubMedCentralPubMedCrossRefGoogle Scholar
  38. Magloire H, Couble ML, Thivichon-Prince B, Maurin JC, Bleicher F (2009) Odontoblast: a mechano-sensory cell. J Exp Zool B Mol Dev Evol 312B:416–424. doi: 10.1002/jez.b.21264 PubMedCrossRefGoogle Scholar
  39. Maurin JC, Couble ML, Staquet MJ, Carrouel F, About I, Avila J, Magloire H, Bleicher F (2009) Microtubule-associated protein 1b, a neuronal marker involved in odontoblast differentiation. J Endod 35:992–996. doi: 10.1016/j.joen.2009.04.009 PubMedCrossRefGoogle Scholar
  40. Michalczyk K, Ziman M (2005) Nestin structure and predicted function in cellular cytoskeletal organisation. Histol Histopathol 20:665–671PubMedGoogle Scholar
  41. Miyazaki T, Kanatani N, Rokutanda S, Yoshida C, Toyosawa S, Nakamura R, Takada S, Komori T (2008) Inhibition of the terminal differentiation of odontoblasts and their transdifferentiation into osteoblasts in Runx2 transgenic mice. Arch Histol Cytol 71:131–146PubMedCrossRefGoogle Scholar
  42. Nishikawa S, Kitamura H (1987) Microtubules, intermediate filaments, and actin filaments in the odontoblast of rat incisor. Anat Rec 219:144–151. doi: 10.1002/ar.1092190206 PubMedCrossRefGoogle Scholar
  43. Otto F, Thornell AP, Crompton T, Denzel A, Gilmour KC, Rosewell IR, Stamp GW, Beddington RS, Mundlos S, Olsen BR, Selby PB, Owen MJ (1997) Cbfa1, a candidate gene for cleidocranial dysplasia syndrome, is essential for osteoblast differentiation and bone development. Cell 89:765–771PubMedCrossRefGoogle Scholar
  44. Quackenbush J (2002) Microarray data normalization and transformation. Nat Genet 32(Suppl):496–501. doi: 10.1038/ng1032 PubMedCrossRefGoogle Scholar
  45. Quispe-Salcedo A, Ida-Yonemochi H, Nakatomi M, Ohshima H (2012) Expression patterns of nestin and dentin sialoprotein during dentinogenesis in mice. Biomed Res 33:119–132PubMedCrossRefGoogle Scholar
  46. Ruch JV, Lesot H, Begue-Kirn C (1995) Odontoblast differentiation. Int J Dev Biol 39:51–68PubMedGoogle Scholar
  47. Sasaki T, Garant PR (1996) Structure and organization of odontoblasts. Anat Rec 245:235–249. doi: 10.1002/(SICI)1097-0185(199606)245:2<235::AID-AR10>3.0.CO;2-Q PubMedCrossRefGoogle Scholar
  48. Sigal MJ, Aubin JE, Ten Cate AR (1985) An immunocytochemical study of the human odontoblast process using antibodies against tubulin, actin, and vimentin. J Dent Res 64:1348–1355PubMedCrossRefGoogle Scholar
  49. Takei Y, Teng J, Harada A, Hirokawa N (2000) Defects in axonal elongation and neuronal migration in mice with disrupted tau and map1b genes. J Cell Biol 150:989–1000PubMedCentralPubMedCrossRefGoogle Scholar
  50. Tint I, Slaughter T, Fischer I, Black MM (1998) Acute inactivation of tau has no effect on dynamics of microtubules in growing axons of cultured sympathetic neurons. J Neurosci 18:8660–8673PubMedGoogle Scholar
  51. Yamashiro T, Aberg T, Levanon D, Groner Y, Thesleff I (2002) Expression of Runx1, -2 and -3 during tooth, palate and craniofacial bone development. Mech Dev 119 (Suppl 1):S107–S110PubMedCrossRefGoogle Scholar
  52. Yan Y, Yang J, Bian W, Jing N (2001) Mouse nestin protein localizes in growth cones of P19 neurons and cerebellar granule cells. Neurosci Lett 302:89–92PubMedCrossRefGoogle Scholar
  53. Yoshida CA, Yamamoto H, Fujita T, Furuichi T, Ito K, Inoue K, Yamana K, Zanma A, Takada K, Ito Y, Komori T (2004) Runx2 and Runx3 are essential for chondrocyte maturation, and Runx2 regulates limb growth through induction of Indian hedgehog. Genes Dev 18:952–963. doi: 10.1101/gad.1174704 PubMedCentralPubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  • Toshihiro Miyazaki
    • 1
  • Tomomi T. Baba
    • 2
  • Masako Mori
    • 1
  • Takeshi Moriishi
    • 1
  • Toshihisa Komori
    • 1
  1. 1.Department of Cell Biology, Unit of Basic Medical SciencesNagasaki University Graduate School of Biomedical SciencesNagasakiJapan
  2. 2.Department of Oral Molecular Biology, Unit of Basic Medical SciencesNagasaki University Graduate School of Biomedical SciencesNagasakiJapan

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