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Nerve-dependent and -independent tenascin expression in the developing chick limb bud
B Wehrle-Haller1, M Koch, S Baumgartner
1Department of Biophysical Chemistry, Biocenter of the University, Basel, Switzerland.
Development (Cambridge, England)
|June 1, 1991
Summary
Glial cells produce tenascin, an extracellular matrix protein crucial for nerve development. Tenascin aids axon penetration and fasciculation during limb morphogenesis, with tendon primordia also playing a guiding role.
Area of Science:
- Developmental Biology
- Neuroscience
- Extracellular Matrix Research
Background:
- Tenascin, an extracellular matrix protein, is dynamically expressed during organogenesis.
- Tenascin is observed along developing peripheral nerves entering the limb mesenchyme.
Purpose of the Study:
- To identify the cellular origin of tenascin deposited along developing nerves.
- To investigate the role of tenascin in nerve development and limb morphogenesis, particularly in relation to innervation and tendon formation.
Main Methods:
- In situ hybridization using a tenascin cDNA probe to detect tenascin mRNA.
- Analysis of normal and nerve-free (nerveless) wing grafts.
Main Results:
- Tenascin mRNA is initially detected in developing limb nerves, originating from vinculin-positive glial precursor cells.
- In nerve-free grafts, tenascin is expressed in tendon primordia independently of innervation.
- Tendon primordia tenascin transiently surrounds developing nerves; later, tenascin expression shifts to perichondrium and tendons.
Conclusions:
- Glial tenascin is essential for facilitating axon penetration into the limb bud and for nerve fasciculation.
- Early tendon primordia may contribute to guiding the migration of axons and glial precursor cells.