Development 129, 5323-5337 5323 © 2002 The Company of Biologists Ltd doi:10.1242/dev.00100 Shh signaling within the dental epithelium is necessary for cell proliferation, growth and polarization Amel Gritli-Linde1,*, Marianna Bei2, Richard Maas2, Xiaoyan M. Zhang3, Anders Linde1 and Andrew P. McMahon4,* 1Department of Oral Biochemistry, Sahlgrenska Academy at Göteborg University, SE-405 30 Göteborg, Sweden 2Division of Genetics, Brigham and Women’s Hospital, Harvard Medical School, 20 Shattuck Street, Boston, MA 02115, USA 3Curis Inc., 45 Moulton Street, Cambridge, MA 02138, USA 4Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02135, USA *Authors for correspondence (e-mail:
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[email protected]) Accepted 12 August 2002 SUMMARY Sonic hedgehog (Shh), a member of the mammalian epithelium should block Shh signaling within dental Hedgehog (Hh) family, plays a key role during epithelial derivatives while preserving normal embryogenesis and organogenesis. Tooth development, mesenchymal signaling. Here we show that Shh-dependent odontogenesis, is governed by sequential and reciprocal interactions occur within the dental epithelium itself. The epithelial-mesenchymal interactions. Genetic removal of dental mesenchyme develops normally up until birth. In Shh activity from the dental epithelium, the sole source of contrast, dental epithelial derivatives show altered Shh during tooth development, alters tooth growth and proliferation, growth, differentiation and polarization.