BACKGROUND: The mouse embryonic mandible comprises two types of tooth primordia in the cheek region: progressive tooth primordia of prospective functional teeth and rudimentary tooth primordia in premolar region - MS and R2. Mice lacking Sprouty genes develop supernumerary tooth in front of the lower M1 (first molar) primordium during embryogenesis. We focused on temporal-spatial dynamics of Sonic Hedgehog expression as a marker of early odontogenesis during supernumerary tooth development. RESULTS: Using mouse embryos with different dosages of Spry2 and Spry4 genes, we showed that during the normal development of M1 in the mandible the sooner appearing Shh signaling domain of the R2 bud transiently coexisted with the later appearing Shh expression domain in the early M1 primordium. Both domains subsequently fused together to form the typical signaling center representing primary enamel knot (pEK) of M1 germ at embryonic day (E) 14.5. However, in embryos with lower Spry2;Spry4 gene dosages, we observed a non-fusion of original R2 and M1 Shh signaling domains with consequent formation of a supernumerary tooth primordium from the isolated R2 bud. CONCLUSIONS: Our results bring new insight to the development of the first lower molar of mouse embryos and define simple tooth unit capable of individual development, as well as determine its influence on normal and abnormal development of the tooth row which reflect evolutionarily conserved tooth pattern. Our findings contribute significantly to existing knowledge about supernumerary tooth formation.

Department of Anthropology and Human Genetics Faculty of Science Charles University Prague Czech Republic

Institute of Experimental Medicine Academy of Sciences of the Czech Republic Prague Czech Republic

Zobrazit více v PubMed

Peterkova R, Peterka M, Viriot L, Lesot H. Development of the vestigial tooth primordia as part of mouse odontogenesis. Connect Tissue Res. 2002;43:120–8. doi: 10.1080/03008200290000745. PubMed DOI

Viriot L, Lesot H, Vonesch JL, Ruch JV, Peterka M, Peterkova R. The presence of rudimentary odontogenic structures in the mouse embryonic mandible requires reinterpretation of developmental control of first lower molar histomorphogenesis. Int J Dev Biol. 2000;44:233–40. PubMed

Peterkova R, Peterka M, Viriot L, Lesot H. Dentition development and budding morphogenesis. J Craniofac Genet Dev Biol. 2000;20:158–72. PubMed

Prochazka J, Pantalacci S, Churava S, Rothova M, Lambert A, Lesot H, et al. Patterning by heritage in mouse molar row development. Proc Natl Acad Sci U S A. 2010;107:15497–502. doi: 10.1073/pnas.1002784107. PubMed DOI PMC

Vaahtokari A, Aberg T, Jernvall J, Keranen S, Thesleff I. The enamel knot as a signaling center in the developing mouse tooth. Mech Dev. 1996;54:39–43. doi: 10.1016/0925-4773(95)00459-9. PubMed DOI

Jernvall J, Kettunen P, Karavanova I, Martin LB, Thesleff I. Evidence for the role of the enamel knot as a control center in mammalian tooth cusp formation - nondividing cells express growth-stimulating FGF-4 gene. Int J Dev Biol. 1994;38:463–9. PubMed

Thesleff I, Jernvall J. The enamel knot: a putative signaling center regulating tooth development. Cold Spring Harb Symp Quant Biol. 1997;62:257–67. doi: 10.1101/SQB.1997.062.01.032. PubMed DOI

Vaahtokari A, Aberg T, Thesleff I. Apoptosis in the developing tooth: association with an embryonic signaling center and suppression by EGF and FGF-4. Development. 1996;122:121–9. PubMed

Bitgood MJ, McMahon AP. Hedgehog and BMP genes are coexpressed at many diverse sites of cell-cell interaction in the mouse embryo. Dev Biol. 1995;172:126–38. doi: 10.1006/dbio.1995.0010. PubMed DOI

Iseki S, Araga A, Ohuchi H, Nohno T, Yoshioka H, Hayashi F, et al. Sonic hedgehog is expressed in epithelial cells during development of whisker, hair, and tooth. Biochem Biophys Res Commun. 1996;218:688–93. doi: 10.1006/bbrc.1996.0123. PubMed DOI

Sarkar L, Cobourne M, Naylor S, Smalley M, Dale T, Sharpe PT. Wnt/Shh interactions regulate ectodermal boundary formation during mammalian tooth development. Proc Natl Acad Sci U S A. 2000;97:4520–4. doi: 10.1073/pnas.97.9.4520. PubMed DOI PMC

Klein O, Kangas A, Jernvall J, Peterkova R, Peterka M, Martin G, et al. Loss of Sprouty2 leads to development of supernumerary teeth by modulating FGF signaling. Mech Dev. 2005;122:S75.

Klein OD, Minowada G, Peterkova R, Kangas A, Yu BD, Lesot H, et al. Sprouty genes control diastema tooth development via bidirectional antagonism of epithelial-mesenchymal FGF signaling. Dev Cell. 2006;11:181–90. doi: 10.1016/j.devcel.2006.05.014. PubMed DOI PMC

Peterkova R, Hovorakova M, Peterka M, Lesot H. Three-dimensional analysis of the early development of the dentition. Aust Dent J. 2014;59:55–80. doi: 10.1111/adj.12130. PubMed DOI PMC

Yahya-Graison EA, Aubert J, Dauphinot L, Rivals I, Prieur M, Golfier G, et al. Classification of human chromosome 21 gene-expression variations in down syndrome: Impact on disease phenotypes. Am J Hum Genet. 2007;81:475–91. doi: 10.1086/520000. PubMed DOI PMC

Makarevitch I, Phillips RL, Springer NM. Profiling expression changes caused by a segmental aneuploid in maize. BMC Genomics. 2008;9:13. doi: 10.1186/1471-2164-9-7. PubMed DOI PMC

Lindsley DL, Sandler L, Jacobs PA, Nozawa H, Parry DM, Carpente A, et al. Segmental aneuploidy and genetic gross structure of Drosophila genome. Genetics. 1972;71:157. PubMed PMC

Ahn Y, Sanderson BW, Klein OD, Krumlauf R. Inhibition of Wnt signaling by Wise (Sostdc1) and negative feedback from Shh controls tooth number and patterning. Development. 2010;137:3221–31. doi: 10.1242/dev.054668. PubMed DOI PMC

Charles C, Hovorakova M, Ahn Y, Lyons DB, Marangoni P, Churava S, et al. Regulation of tooth number by fine-tuning levels of receptor-tyrosine kinase signaling. Development. 2011;138:4063–73. doi: 10.1242/dev.069195. PubMed DOI PMC

Peterkova R, Peterka M, Vonesch JL, Ruch JV. Contribution of 3-D computer-assisted reconstructions to the study of the initial steps of mouse odontogenesis. Int J Dev Biol. 1995;39:239–47. PubMed

Peterkova R, Lesot H, Vonesch JL, Peterka M, Ruch JV. Mouse molar morphogenesis revisited by three dimensional reconstruction.1. Analysis of initial stages of the first upper molar development revealed two transient buds. Int J Dev Biol. 1996;40:1009–16. PubMed

Lesot H, Peterkova R, Viriot L, Vonesch JL, Tureckova J, Peterka M, et al. Early stages of tooth morphogenesis in mouse analyzed by 3D reconstructions. Eur J Oral Sci. 1998;106:64–70. doi: 10.1111/j.1600-0722.1998.tb02155.x. PubMed DOI

Jernvall J, Thesleff I. Reiterative signaling and patterning during mammalian tooth morphogenesis. Mech Dev. 2000;92:19–29. doi: 10.1016/S0925-4773(99)00322-6. PubMed DOI

Cho SW, Lee HA, Cai JL, Lee MJ, Kim JY, Ohshima H, et al. The primary enamel knot determines the position of the first buccal cusp in developing mice molars. Differentiation. 2007;75:441–51. doi: 10.1111/j.1432-0436.2006.00153.x. PubMed DOI

Lan Y, Jia SH, Jiang RL. Molecular patterning of the mammalian dentition. Semin Cell Dev Biol. 2014;25:61–70. doi: 10.1016/j.semcdb.2013.12.003. PubMed DOI PMC

Townsend G, Bockmann M, Hughes T, Brook A. Genetic, environmental and epigenetic influences on variation in human tooth number, size and shape. Odontology. 2012;100:1–9. doi: 10.1007/s10266-011-0052-z. PubMed DOI

Wang XP, Fan JB. Molecular genetics of supernumerary tooth formation. Genesis. 2011;49:261–77. doi: 10.1002/dvg.20715. PubMed DOI PMC

Mustonen T, Pispa J, Mikkola ML, Pummila M, Kangas AT, Pakkasjarvi L, et al. Stimulation of ectodermal organ development by ectodysplasin-A1. Dev Biol. 2003;259:123–36. doi: 10.1016/S0012-1606(03)00157-X. PubMed DOI

Mustonen T, Ilmonen M, Pummila M, Kangas AT, Laurikkala J, Jaatinen R, et al. Ectodysplasin A1 promotes placodal cell fate during early morphogenesis of ectodermal appendages. Development. 2004;131:4907–19. doi: 10.1242/dev.01377. PubMed DOI

Kassai Y, Munne P, Hotta YH, Penttila E, Kavanagh K, Ohbayashi N, et al. Regulation of mammalian tooth cusp patterning by ectodin. Science. 2005;309:2067–70. doi: 10.1126/science.1116848. PubMed DOI

Lagronova-Churava S, Spoutil F, Vojtechova S, Lesot H, Peterka M, Klein OD, et al. The dynamics of supernumerary tooth development are differentially regulated by sprouty genes. J Exp Zool Part B Mol Dev Evol. 2013;320B:307–20. doi: 10.1002/jez.b.22502. PubMed DOI

Kist R, Watson M, Wang XM, Cairns P, Miles C, Reid DJ, et al. Reduction of Pax9 gene dosage in an allelic series of mouse mutants causes hypodontia and oligodontia. Hum Mol Genet. 2005;14:3605–17. doi: 10.1093/hmg/ddi388. PubMed DOI

Welsh IC, Hagge-Greenberg A, O’Brien TP. A dosage-dependent role for Spry2 in growth and patterning during palate development. Mech Dev. 2007;124:746–61. doi: 10.1016/j.mod.2007.06.007. PubMed DOI PMC

Hacohen N, Kramer S, Sutherland D, Hiromi Y, Krasnow MA. Sprouty encodes a novel antagonist of FGF signaling that patterns apical branching of the Drosophila airways. Cell. 1998;92:253–63. doi: 10.1016/S0092-8674(00)80919-8. PubMed DOI

Shim K, Minowada G, Coling DE, Martin GR. Sprouty2, a mouse deafness gene, regulates cell fate decisions in the auditory sensory epithelium by antagonizing FGF signaling. Dev Cell. 2005;8:553–64. doi: 10.1016/j.devcel.2005.02.009. PubMed DOI

Kim HJ, Bar-Sagi D. Modulation of signalling by sprouty: a developing story. Nat Rev Mol Cell Biol. 2004;5:441–50. doi: 10.1038/nrm1400. PubMed DOI

Peterkova R, Churava S, Lesot H, Rothova M, Prochazka J, Peterka M, et al. Revitalization of a diastemal tooth primordium in Spry2 null mice results from increased proliferation and decreased apoptosis. J Exp Zool Part B Mol Dev Evol. 2009;312B:292–308. doi: 10.1002/jez.b.21266. PubMed DOI PMC

Kettunen P, Thesleff I. Expression and function of FGFs-4, −8, and −9 suggest functional redundancy and repetitive use as epithelial signals during tooth morphogenesis. Dev Dyn. 1998;211:256–68. doi: 10.1002/(SICI)1097-0177(199803)211:3<256::AID-AJA7>3.0.CO;2-G. PubMed DOI

Klein OD, Lyons DB, Balooch G, Marshall GW, Basson MA, Peterka M, et al. An FGF signaling loop sustains the generation of differentiated progeny from stem cells in mouse incisors. Development. 2008;135:377–85. doi: 10.1242/dev.015081. PubMed DOI PMC

Kettunen P, Laurikkala J, Itaranta P, Vainio S, Itoh N, Thesleff I. Associations of FGF-3 and FGF-10 with signaling networks regulating tooth morphogenesis. Dev Dyn. 2000;219:322–32. doi: 10.1002/1097-0177(2000)9999:9999<::AID-DVDY1062>3.0.CO;2-J. PubMed DOI

Kratochwil K, Galceran J, Tontsch S, Roth W, Grosschedl R. FGF4, a direct target of LEF1 and Wnt signaling, can rescue the arrest of tooth organogenesis in Lef1(−/−) mice. Genes Dev. 2002;16:3173–85. doi: 10.1101/gad.1035602. PubMed DOI PMC

Sun X, Lewandoski M, Meyers EN, Liu YH, Maxson RE, Martin GR. Conditional inactivation of Fgf4 reveals complexity of signalling during limb bud development. Nat Genet. 2000;25:83–6. doi: 10.1038/75644. PubMed DOI

Ohazama A, Johnson EB, Ota MS, Choi HJ, Porntaveetus T, Oommen S, et al. Lrp4 modulates extracellular integration of cell signaling pathways in development. PLos One. 2008;3:11. doi: 10.1371/journal.pone.0004092. PubMed DOI PMC

Le YZ, Miller JL, Sauer B. GFPcre fusion vectors with enhanced expression. Anal Biochem. 1999;270:334–6. doi: 10.1006/abio.1999.4110. PubMed DOI

Harfe BD, Scherz PJ, Nissim S, Tian F, McMahon AP, Tabin CJ. Evidence for an expansion-based temporal Shh gradient in specifying vertebrate digit identities. Cell. 2004;118:517–28. doi: 10.1016/j.cell.2004.07.024. PubMed DOI

Peterka M, Lesot H, Peterkova R. Body weight in mouse embryos specifies staging of tooth development. Connect Tissue Res. 2002;43:186–90. doi: 10.1080/03008200290000673. PubMed DOI

Hayashi S, McMahon AP. Efficient recombination in diverse tissues by a tamoxifen-inducible form of Cre: a tool for temporally regulated gene activation/inactivation in the mouse. Dev Biol. 2002;244:305–18. doi: 10.1006/dbio.2002.0597. PubMed DOI

Taniguchi K, Ayada T, Ichiyama K, Kohno R, Yonemitsu Y, Minami Y, et al. Sprouty2 and Sprouty4 are essential for embryonic morphogenesis and regulation of FGF signaling. Biochem Biophys Res Commun. 2007;352:896–902. doi: 10.1016/j.bbrc.2006.11.107. PubMed DOI

Sprouty2/4 deficiency disrupts early signaling centers impacting chondrogenesis in the mouse forelimb

Developmental variability channels mouse molar evolution

Modeling Edar expression reveals the hidden dynamics of tooth signaling center patterning

Transcriptomic signatures shaped by cell proportions shed light on comparative developmental biology