PUBLICATION

Neuropilin-1a is involved in trunk motor axon outgrowth in embryonic zebrafish

Authors

Feldner, J., Becker, T., Goishi, K., Schweitzer, J., Lee, P., Schachner, M., Klagsbrun, M., and Becker, C.G.

ID

ZDB-PUB-050823-8

Date

2005

Source

Developmental Dynamics : an official publication of the American Association of Anatomists 234(3): 535-549 (Journal)

Registered Authors

Becker, Catherina G., Becker, Thomas, Feldner, Julia, Goishi, Katsutoshi, Schachner, Melitta, Schweitzer, Jörn

Keywords

axon guidance, angiogenesis, semaphorin, VEGF, primary motor neurons

MeSH Terms

Semaphorin-3A/metabolism
Vascular Endothelial Growth Factor A/pharmacology
Phenotype
Motor Neurons/drug effects
Motor Neurons/metabolism*
Animals
Zebrafish/embryology*
Zebrafish/genetics
Zebrafish/metabolism*
RNA, Messenger/genetics
RNA, Messenger/metabolism
Neuropilin-1/genetics
Neuropilin-1/metabolism*
Gene Expression Regulation, Developmental/drug effects
Axons/drug effects
Axons/physiology*

(all 16)

PubMed

16110501 Full text @ Dev. Dyn.

Abstract

Neuropilin-1, a receptor for axon-repellent semaphorins and vascular endothelial growth factor (VEGF), functions both in angiogenesis and axon growth. Here, we show strong expression of neuropilin-1a in primary motor neurons in the trunk of embryonic zebrafish. Reducing the expression of neuropilin-1a using antisense morpholino oligonucleotides induced aberrant branching of motor nerves, additional exit points of motor nerves from the spinal cord, and migration of neurons out of the spinal cord along the motor axon pathway in a dose-dependent manner. These phenotypes could be partially rescued by coinjecting neuropilin-1a mRNA. Other axons in the spinal cord and head appeared unaffected by the morpholino treatment. In addition, neuropilin-1a morpholino treatment disturbed normal formation of blood vessels in the trunk of 24 hours postfertilization embryos, as shown by microangiography. Morpholinos to VEGF also disturbed formation of blood vessels but did not affect motor axons, indicating that correct formation of blood vessels is not needed for the growth of primary motor axons. Morpholinos to the semaphorin 3A homologs semaphorin 3A1 and semaphorin 3A2 also had no effect on motor axon growth. However, combined injections of neuropilin-1a morpholino, at a concentration that did not elicit axonal aberrations when injected alone, with VEGF, semaphorin 3A1, or semaphorin 3A2 morpholinos synergistically increased the proportion of embryos showing aberrant motor axon growth. Thus, neuropilin-1a in primary motor neurons may integrate signals from several ligands and is needed for proper segmental growth of primary motor nerves in zebrafish.

Genes / Markers

Figures