Distinct roles for secreted semaphorin signaling in spinal motor axon guidance

Andrea B Huber; Artur Kania; Tracy S Tran; Chenghua Gu; Natalia De Marco Garcia; Ivo Lieberam; Dontais Johnson; Thomas M Jessell; David D Ginty; Alex L Kolodkin

doi:10.1016/j.neuron.2005.12.003

Distinct roles for secreted semaphorin signaling in spinal motor axon guidance

Neuron. 2005 Dec 22;48(6):949-64. doi: 10.1016/j.neuron.2005.12.003.

Authors

Andrea B Huber¹, Artur Kania, Tracy S Tran, Chenghua Gu, Natalia De Marco Garcia, Ivo Lieberam, Dontais Johnson, Thomas M Jessell, David D Ginty, Alex L Kolodkin

Affiliation

¹ Howard Hughes Medical Institute, Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.

PMID: 16364899
DOI: 10.1016/j.neuron.2005.12.003

Abstract

Neuropilins, secreted semaphorin coreceptors, are expressed in discrete populations of spinal motor neurons, suggesting they provide critical guidance information for the establishment of functional motor circuitry. We show here that motor axon growth and guidance are impaired in the absence of Sema3A-Npn-1 signaling. Motor axons enter the limb precociously, showing that Sema3A controls the timing of motor axon in-growth to the limb. Lateral motor column (LMC) motor axons within spinal nerves are defasciculated as they grow toward the limb and converge in the plexus region. Medial and lateral LMC motor axons show dorso-ventral guidance defects in the forelimb. In contrast, Sema3F-Npn-2 signaling guides the axons of a medial subset of LMC neurons to the ventral limb, but plays no major role in regulating their fasciculation. Thus, Sema3A-Npn-1 and Sema3F-Npn-2 signaling control distinct steps of motor axon growth and guidance during the formation of spinal motor connections.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Animals
Body Patterning / physiology
Brachial Plexus / embryology
Cell Differentiation / physiology
Chick Embryo
Forelimb / embryology
Forelimb / innervation
Gene Expression Regulation, Developmental / physiology
Growth Cones / metabolism*
Growth Cones / ultrastructure
Hindlimb / embryology
Hindlimb / innervation
Limb Buds / embryology
Limb Buds / innervation
Lumbosacral Plexus / embryology
Membrane Proteins / genetics
Membrane Proteins / metabolism
Mice
Motor Neurons / cytology
Motor Neurons / metabolism*
Muscle, Skeletal / embryology
Muscle, Skeletal / innervation
Nerve Tissue Proteins / genetics
Nerve Tissue Proteins / metabolism
Neuropilin-1 / genetics
Neuropilin-1 / metabolism
Neuropilin-2 / genetics
Neuropilin-2 / metabolism
Neuropilins / metabolism*
Semaphorin-3A / genetics
Semaphorin-3A / metabolism
Semaphorins / metabolism*
Signal Transduction / physiology*
Spinal Cord / cytology
Spinal Cord / embryology*
Spinal Cord / metabolism

Substances

Membrane Proteins
Nerve Tissue Proteins
Neuropilin-2
Neuropilins
Sema3a protein, mouse
Sema3f protein, mouse
Semaphorin-3A
Semaphorins
Neuropilin-1