Article

Nature 425, 926-933 (30 October 2003) | doi:10.1038/nature02051; Received 22 July 2003; Accepted 3 September 2003

Motor neuron columnar fate imposed by sequential phases of Hox-c activity

Jeremy S. Dasen1, Jeh-Ping Liu2 & Thomas M. Jessell1

  1. Howard Hughes Medical Institute, Department of Biochemistry and Molecular Biophysics, Center for Neurobiology and Behavior, Columbia University, 701 West 168th Street, New York, New York 10032, USA
  2. University of Virginia School of Medicine, Department of Neuroscience, Lane Road extended, MR4, Room 5032, Charlottesville, Virginia 22908, USA

Correspondence to: Jeremy S. Dasen1Thomas M. Jessell1 Email: tmj1@columbia.edu
Email: jd2009@columbia.edu

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The organization of neurons into columns is a prominent feature of central nervous system structure and function. In many regions of the central nervous system the grouping of neurons into columns links cell-body position to axonal trajectory, thus contributing to the establishment of topographic neural maps. This link is prominent in the developing spinal cord, where columnar sets of motor neurons innervate distinct targets in the periphery. We show here that sequential phases of Hox-c protein expression and activity control the columnar differentiation of spinal motor neurons. Hox expression in neural progenitors is established by graded fibroblast growth factor signalling and translated into a distinct motor neuron Hox pattern. Motor neuron columnar fate then emerges through cell autonomous repressor and activator functions of Hox proteins. Hox proteins also direct the expression of genes that establish motor topographic projections, thus implicating Hox proteins as critical determinants of spinal motor neuron identity and organization.