IADR Abstract Archives
Role of Wnt Signaling in the Regulation of Tooth Development in Zebrafish
Objectives: Wnt signaling is recognized as one of the important pathway for tooth development, but the exact role of Wnt signaling for the sequential tooth development in different developmental stages has not been obviously proved. Zebrafish is an unique vertebrate model for the study of odontogenesis which has sequential tooth. In this study, we investigated the role of the Wnt signaling for each particular developmental stage in the development of the first and sequential tooth in zebrafish.
Methods: Reporter transgenics including nf-kb:EGFP and tcf/Lef-miniP:dGFP were used to visualize the morphology of the dental epithelium and the spatio-temporal pattern of Wnt signaling. Wnt signaling activity were manipulated at various tooth developmental stage using the heat-shock-inducible transgenics hsp70:Dkk1-GFP or a Wnt agonist (BIO; 6-bromoindirubi-3’-oxime).
Results: The sequential tooth was subsequently developed from epithelial outgrowth of the first tooth. Inhibition of Wnt signaling caused the arrest of tooth development at early stage, and delay in the development of the first tooth also delays the onset of initiation for the second tooth. Interestingly, the heat-shock at the time of first tooth placode irreversibly arrests the second tooth and causes ‘double teeth’. In addition, the heat-shock during morphogenesis decreases the tooth size. Over-activation of the Wnt signaling blocks the development of sequential tooth, but not first tooth.
Conclusions: The sequential tooth is more vulnerable to the changes in Wnt signaling than the first tooth. These results imply that the Wnt signaling during the development of sequential tooth affect to the overall number of tooth
Methods: Reporter transgenics including nf-kb:EGFP and tcf/Lef-miniP:dGFP were used to visualize the morphology of the dental epithelium and the spatio-temporal pattern of Wnt signaling. Wnt signaling activity were manipulated at various tooth developmental stage using the heat-shock-inducible transgenics hsp70:Dkk1-GFP or a Wnt agonist (BIO; 6-bromoindirubi-3’-oxime).
Results: The sequential tooth was subsequently developed from epithelial outgrowth of the first tooth. Inhibition of Wnt signaling caused the arrest of tooth development at early stage, and delay in the development of the first tooth also delays the onset of initiation for the second tooth. Interestingly, the heat-shock at the time of first tooth placode irreversibly arrests the second tooth and causes ‘double teeth’. In addition, the heat-shock during morphogenesis decreases the tooth size. Over-activation of the Wnt signaling blocks the development of sequential tooth, but not first tooth.
Conclusions: The sequential tooth is more vulnerable to the changes in Wnt signaling than the first tooth. These results imply that the Wnt signaling during the development of sequential tooth affect to the overall number of tooth