Beta-Catenin and Plakoglobin Expression during Zebrafish Tooth Development and Replacement.

Barbara Verstraeten,Jolanda Van Hengel,Ann Huysseune

doi:10.1371/journal.pone.0148114

Abstract

We analyzed the protein distribution of two cadherin-associated molecules, plakoglobin and β-catenin, during the different stages of tooth development and tooth replacement in zebrafish. Plakoglobin was detected at the plasma membrane already at the onset of tooth development in the epithelial cells of the tooth. This pattern remained unaltered during further tooth development. The mesenchymal cells only showed plakoglobin from cytodifferentiation onwards. Plakoglobin 1a morpholino-injected embryos showed normal tooth development with proper initiation and differentiation. Although plakoglobin is clearly present during normal odontogenesis, the loss of plakoglobin 1a does not influence tooth development. β-catenin was found at the cell borders of all cells of the successional lamina but also in the nuclei of surrounding mesenchymal cells. Only membranous, not nuclear, β-catenin, was found during morphogenesis stage. However, during cytodifferentiation stage, both nuclear and membrane-bound β-catenin was detected in the layers of the enamel organ as well as in the differentiating odontoblasts. Nuclear β-catenin is an indication of an activated Wnt pathway, therefore suggesting a possible role for Wnt signalling during zebrafish tooth development and replacement.

Highlights

During the various phases of development of the vertebrate body, it is of major importance that cells are capable of communicating with each other and of rearranging themselves
Cadherins represent an important family of cell adhesion molecules, and include classical cadherins and desmosomal cadherins
Distribution of plakoglobin during zebrafish tooth development and replacement At 48 hpf, plakoglobin is present in the pharyngeal epithelium as dots on the plasma membrane, restricted to the side facing the pharyngeal lumen

Summary

Introduction

During the various phases of development of the vertebrate body, it is of major importance that cells are capable of communicating with each other and of rearranging themselves. Adhesion molecules play a very important role during the morphogenetic processes that underlie development [1,2,3,4]. There are different types of cell junctions. Adherens junctions (AJs) are an important type of intercellular junction, consisting of the cadherin-catenin complex. Cadherins represent an important family of cell adhesion molecules, and include classical cadherins and desmosomal cadherins. Classical cadherins are connected to the actin cytoskeleton through β-catenin. At the cell membrane the cadherins cluster laterally to achieve strong adhesive forces.

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Conclusion