Asian Science Seminar ASS-2

Sequential expression of Notch1, HES5, Jagged2, and Math1 in molar tooth germ of mouse

Silvia Susana Borkosky^{1, 2}, Naoki Katase², Phuu Pwint Han^{2, 3}, Mehmet Gunduz² and Hitoshi Nagatsuka²

¹Department of Oral Pathology. Tucuman National University, School of Dentistry. Tucuman, Argentina

²Department of Oral Pathology and Medicine. Graduate School of Medicine, Dentistry and Pharmaceutical Sciences. Okayama University. Okayama, Japan

³Institute of Dental Medicine. Yangon, Myanmar

The Notch signaling is an evolutionary conserved mechanism that plays an important role in cell-cell communication and cell fate in a wide range of tissues. Notch regulates cell fate decisions through two different mechanisms: lateral specification and inductive signaling.

Expression of Notch1, HES5, Jagged2 and Math1 were analyzed at the molar tooth germ during embryonic stage (E) 13 and E15 and during postnatal stage (PN) 1, PN3, PN5, PN10 and PN14 by using in situ hybridization. Positive Notch1 expression was found at the tooth bud during embryonic stages, but its expression was absent from the basal cells in contact with the dental mesenchyme. Later, during postnatal stages Notch1 appeared briefly expressed at the differentiated ameloblasts and odontoblasts. HES5 showed weak or absence of expression through all stages. Jagged2 and Math1 were strongly expressed at the differentiated ameloblasts and odontoblasts and Math1 strong expression was even maintained until PN14 stage. Math1 showed the strongest expression in contrast to the weakest expression of HES5. Our results suggest that the Nocth1 signaling pathway through Jagged2 has an important effect on Math1, regulating odontogenesis through both mechanisms lateral specification and inductive signaling.