BBB seminar: Ann Huysseune
How to make and to replace a tooth: lessons from zebrafish
Biology Department, Ghent University, Belgium
The dentition of vertebrates (including mammals) evolved from a condition with simple conical teeth, showing continuous replacement, to a condition with teeth of a highly complex shape, and in mammals being replaced only once, at the most. To understand the mechanism responsible for continuous tooth replacement, study of a model organism which represents characters of an ancestral state, and for which a wide array of tools is available to address developmental questions, presents unquestionable advantages.
The zebrafish (Danio rerio) has become such a model for genetic, molecular and developmental studies. Although its teeth are restricted to the last branchial arch, they are homologous to other vertebrate teeth. The zebrafish dentition can be used as a paradigm to address questions such as endodermal participation in the formation of teeth, epithelial primacy in tooth initiation, factors that control renewed initiation of teeth, etc.
In my presentation I will introduce the audience to the dentition in different life stages of the zebrafish, and explain why understanding the tooth replacement pattern is vital for addressing questions of odontogenesis in this model. Next, I will highlight some particularities related to the structure and development of the zebrafish teeth. Finally, I will bring forward arguments in support of the hypothesis that adult epithelial stem cells underlie the process of continuous tooth renewal in the zebrafish (and other polyphyodont vertebrates) and suggest avenues to substantiate this hypothesis. Eventually, answering the question of why the fact that zebrafish (and other vertebrates) are capable to renew their teeth throughout life can open perspectives for applications in human dentistry.