Topographic motor projections in the limb imposed by LIM homeodomain protein regulation of ephrin-A:EphA interactions.
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.
Kania
Artur
A
Howard Hughes Medical Institute, Department of Biochemistry and Molecular Biophysics, Center for Neurobiology and Behavior, Columbia University, New York, NY 10032, USA.
Jessell
Thomas M
TM
D000818:Animals; D001369:Axons / Q000502:physiology; D002642:Chick Embryo; D002678:Chimera; D036385:Ephrin-A4 / Q000235:genetics / Q000378:metabolism*; D005121:Extremities / Q000196:embryology / Q000294:innervation; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D060850:LIM-Homeodomain Proteins; D008648:Mesoderm / Q000166:cytology; D051379:Mice; D009044:Motor Cortex / Q000166:cytology / Q000196:embryology; D009046:Motor Neurons / Q000502:physiology*; D009419:Nerve Tissue Proteins; D036081:Receptors, Eph Family / Q000235:genetics / Q000378:metabolism*; D013116:Spinal Cord / Q000166:cytology / Q000196:embryology / Q000502:physiology*; D014157:Transcription Factors
D036385:Ephrin-A4; D018398:Homeodomain Proteins; C112149:LIM homeobox transcription factor 1 beta; D060850:LIM-Homeodomain Proteins; C499523:Lhx1 protein, mouse; D009419:Nerve Tissue Proteins; D014157:Transcription Factors; C063843:insulin gene enhancer binding protein Isl-1; D036081:Receptors, Eph Family