A Hox regulatory network establishes motor neuron pool identity and target-muscle connectivity

Cell. 2005 Nov 4;123(3):477-91. doi: 10.1016/j.cell.2005.09.009.


Spinal motor neurons acquire specialized "pool" identities that determine their ability to form selective connections with target muscles in the limb, but the molecular basis of this striking example of neuronal specificity has remained unclear. We show here that a Hox transcriptional regulatory network specifies motor neuron pool identity and connectivity. Two interdependent sets of Hox regulatory interactions operate within motor neurons, one assigning rostrocaudal motor pool position and a second directing motor pool diversity at a single segmental level. This Hox regulatory network directs the downstream transcriptional identity of motor neuron pools and defines the pattern of target-muscle connectivity.

Publication types

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

MeSH terms

  • Animals
  • Body Patterning / physiology*
  • Cell Differentiation
  • Chick Embryo
  • Gene Expression Regulation, Developmental
  • Homeodomain Proteins / physiology*
  • Motor Neurons / metabolism
  • Motor Neurons / physiology*
  • Muscle, Skeletal / embryology
  • Muscle, Skeletal / innervation*
  • Spinal Cord / cytology
  • Spinal Cord / embryology
  • Spinal Cord / physiology*
  • Transcription Factors / physiology


  • Homeodomain Proteins
  • Transcription Factors