Abstract
The formation of topographic neural maps relies on the coordinate assignment of neuronal cell body position and axonal trajectory. The projection of motor neurons of the lateral motor column (LMC) along the dorsoventral axis of the limb mesenchyme constitutes a simple topographic map that is organized in a binary manner. We show that LIM homeodomain proteins establish motor neuron topography by coordinating the mediolateral settling position of motor neurons within the LMC with the dorsoventral selection of axon pathways in the limb. These topographic projections are established, in part, through LIM homeodomain protein control of EphA receptors and ephrin-A ligands in motor neurons and limb mesenchymal cells.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Animals
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Axons / physiology
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Chick Embryo
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Chimera
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Ephrin-A4 / genetics
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Ephrin-A4 / metabolism*
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Extremities / embryology
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Extremities / innervation
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Gene Expression Regulation, Developmental / physiology
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Homeodomain Proteins / genetics
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Homeodomain Proteins / metabolism*
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LIM-Homeodomain Proteins
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Mesoderm / cytology
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Mice
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Motor Cortex / cytology
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Motor Cortex / embryology
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Motor Neurons / physiology*
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Nerve Tissue Proteins*
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Receptors, Eph Family / genetics
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Receptors, Eph Family / metabolism*
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Spinal Cord / cytology
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Spinal Cord / embryology
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Spinal Cord / physiology*
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Transcription Factors
Substances
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Ephrin-A4
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Homeodomain Proteins
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LIM homeobox transcription factor 1 beta
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LIM-Homeodomain Proteins
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Lhx1 protein, mouse
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Nerve Tissue Proteins
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Transcription Factors
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insulin gene enhancer binding protein Isl-1
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Receptors, Eph Family