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Tenascin‐C is involved in motor axon outgrowth in the trunk of developing zebrafish
Author(s) -
Schweitzer Jörn,
Becker Thomas,
Lefebvre Julie,
Granato Michael,
Schachner Melitta,
Becker Catherina G.
Publication year - 2005
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/dvdy.20525
Subject(s) - biology , tenascin , zebrafish , tenascin c , extracellular matrix , microbiology and biotechnology , axon , extracellular , anatomy , spinal cord , neuroscience , genetics , gene , fibronectin
Abstract Motor axons in the trunk of the developing zebrafish exit from the ventral spinal cord in one ventral root per hemisegment and grow on a common path toward the region of the horizontal myoseptum, where they select their specific pathways. Tenascin‐C, a component of the extracellular matrix, is concentrated in this choice region. Adaxial cells and other myotomal cells express tenascin‐C mRNA, suggesting that these cells are the source of tenascin‐C protein. Overexpressing an axon repellent fragment containing the cysteine‐rich region and the epidermal growth factor‐like repeats of tenascin‐C led to retarded growth of ventral motor nerves between their spinal exit point and the horizontal myoseptum. Injection of a protein fragment containing the same part of tenascin‐C also induced slower growth of motor nerves. Conversely, knock down of tenascin‐C protein resulted in abnormal lateral branching of ventral motor nerves. In the zebrafish unplugged mutant, in which axons display pathfinding defects in the region of the horizontal myoseptum, tenascin‐C immunoreactivity was not detectable in this region, indicating an abnormal extracellular matrix in unplugged . We conclude that tenascin‐C is part of a specialized extracellular matrix in the region of the horizontal myoseptum that influences the growth of motor axons. Developmental Dynamics 234:550–566, 2005. © 2005 Wiley‐Liss, Inc.