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Death receptor signaling giving life to ectodermal organs
Irma Thesleff1, Marja L Mikkola
1Developmental Biology Program, Insitute of Biotechnology, Viikki Biocenter, PO Box 56, University of Helsinki, 00014 Helsinki, Finland. irma.thesleff@helsinki.fi
Abstract:
A new tumor necrosis factor (TNF) pathway has been identified that has an important function in the regulation of embryonic development. Three key components of this pathway are previously unknown proteins: the TNF ligand ectodysplasin (also known as EDA), its death domain-containing receptor EDAR, and the death domain adapter molecule EDARADD. This pathway was discovered and delineated through the cloning of genes that cause human hypohidrotic ectodermal dysplasia (HED) syndromes and by analysis of the corresponding mouse mutants (Tabby, downless, and crinkled) showing defects in hair, teeth, and several exocrine glands. EDAR signaling is mediated by the activation of nuclear factor kappa B, but other downstream targets are not known. Ectodysplasin-EDAR signaling mediates cell interactions within the ectoderm and regulates the initiation and morphogenesis of hair and teeth. It is also necessary for the development of fish scales, indicating that this pathway and its function have been conserved during the evolution of ectodermal organs.
Insights
A newly discovered tumor necrosis factor (TNF) pathway, involving ectodysplasin (EDA) and EDAR, is crucial for embryonic development. This pathway regulates ectodermal organ formation, including hair and teeth, and is conserved across species.
Area of Science:
- Developmental Biology
- Molecular Biology
- Genetics
Background:
- A novel tumor necrosis factor (TNF) pathway has been identified.
- This pathway plays a critical role in regulating embryonic development.
Purpose of the Study:
- To identify and characterize the components of a new TNF pathway involved in embryonic development.
- To understand the function of this pathway in the formation of ectodermal organs.
Main Methods:
- Cloning of genes responsible for human hypohidrotic ectodermal dysplasia (HED) syndromes.
- Analysis of mouse mutants (Tabby, downless, crinkled) with ectodermal defects.
- Investigation of the ectodysplasin-EDAR signaling pathway.
Main Results:
- Identified three key components: ectodysplasin (EDA), EDAR, and EDARADD.
- Demonstrated that EDAR signaling activates nuclear factor kappa B.
- Showed that ectodysplasin-EDAR signaling regulates hair and tooth morphogenesis and is essential for fish scale development.
Conclusions:
- The ectodysplasin-EDAR pathway is essential for embryonic development of ectodermal organs.
- This pathway mediates cell interactions within the ectoderm.
- The conserved function across species highlights its evolutionary significance in ectodermal organogenesis.