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Live Imaging of Cell Extrusion from the Epidermis of Developing Zebrafish
Published on: June 27, 2011
Tjp3/zo-3 is critical for epidermal barrier function in zebrafish embryos
Tanja K Kiener1, Inna Selptsova-Friedrich, Walter Hunziker
1Epithelial Cell Biology Laboratory, Institute of Molecular and Cell Biology, A*STAR (Agency for Science Technology and Research), Singapore 138673, Singapore.
Developmental Biology
|February 16, 2008
Summary
TJP3/ZO-3 protein is crucial for zebrafish development, maintaining the epidermal barrier and osmoregulation. Its absence causes developmental defects, highlighting its essential role in early embryonic stages.
Area of Science:
- Cell Biology
- Developmental Biology
- Physiology
Background:
- TJP3/ZO-3 is a scaffolding protein linking tight junctions to the cytoskeleton and polarity complexes.
- Its physiological function and in vivo relevance remain largely unknown.
- Previous studies in mice showed no apparent phenotype in TJP3/ZO-3 knockout models.
Purpose of the Study:
- To investigate the physiological function of TJP3/ZO-3 in early vertebrate development.
- To determine the role of TJP3/ZO-3 in the integrity and function of tight junctions.
- To elucidate the impact of TJP3/ZO-3 on epidermal barrier and osmoregulation.
Main Methods:
- Utilized zebrafish (Danio rerio) as a model organism.
- Employed morpholino-mediated knockdown (silencing) of tjp3/zo-3 expression.
- Assessed embryonic phenotypes including edema, circulation, and malformations.
- Analyzed tight junction ultrastructure using electron microscopy.
- Quantified epidermal barrier function by measuring permeability to low molecular weight tracers.
- Evaluated osmoregulation capacity and sensitivity to osmotic stress.
Main Results:
- Tjp3/Zo-3 is a component of tight junctions in the enveloping cell layer of zebrafish embryos.
- Silencing tjp3/zo-3 resulted in significant developmental defects: edema, loss of blood circulation, and tail fin malformations.
- Ultrastructural analysis revealed disrupted tight junctions in the enveloping cell layer of morphant embryos.
- Loss of tjp3/zo-3 impaired epidermal barrier function, increasing permeability and sensitivity to osmotic stress.
- The observed phenotype mimicked the effects of osmotic stress on wild-type embryos, indicating a role in osmoregulation.
Conclusions:
- Tjp3/Zo-3 is essential for maintaining the barrier function of the enveloping cell layer in zebrafish embryos.
- Tjp3/Zo-3 plays a critical role in embryonic osmoregulation.
- This study reveals a vital function for TJP3/ZO-3 in early vertebrate development, contrasting with previous findings in mice.
