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ZFIN ID: ZDB-PUB-030325-2
Autonomous and nonautonomous functions for Hox/Pbx in branchiomotor neuron development
Cooper, K.L., Leisenring, W.M., and Moens, C.B.
Date: 2003
Source: Developmental Biology   253(2): 200-213 (Journal)
Registered Authors: Cooper, Kim, Moens, Cecilia
Keywords: none
MeSH Terms:
  • Animals
  • Animals, Genetically Modified
  • Cell Movement/genetics
  • DNA-Binding Proteins*
  • Facial Nerve/embryology
  • Gene Targeting
  • Genes, Homeobox*
  • Glycosyltransferases/genetics
  • Green Fluorescent Proteins
  • Homeodomain Proteins/genetics
  • Luminescent Proteins/genetics
  • Mosaicism
  • Motor Neurons/cytology*
  • Neural Pathways/embryology
  • Rhombencephalon/embryology
  • Trigeminal Nerve/embryology
  • Zebrafish/genetics*
  • Zebrafish/growth & development*
  • Zebrafish Proteins/genetics
PubMed: 12645925 Full text @ Dev. Biol.
The vertebrate branchiomotor neurons are organized in a pattern that corresponds with the segments, or rhombomeres, of the developing hindbrain and have identities and behaviors associated with their position along the anterior/posterior axis. These neurons undergo characteristic migrations in the hindbrain and project from stereotyped exit points. We show that lazarus/pbx4, which encodes an essential Hox DNA-binding partner in zebrafish, is required for facial (VIIth cranial nerve) motor neuron migration and for axon pathfinding of trigeminal (Vth cranial nerve) motor axons. We show that lzr/pbx4 is required for Hox paralog group 1 and 2 function, suggesting that Pbx interacts with these proteins. Consistent with this, lzr/pbx4 interacts genetically with hoxb1a to control facial motor neuron migration. Using genetic mosaic analysis, we show that lzr/pbx4 and hoxb1a are primarily required cell-autonomously within the facial motor neurons; however, analysis of a subtle non-cell-autonomous effect indicates that facial motor neuron migration is promoted by interactions amongst the migrating neurons. At the same time, lzr/pbx4 is required non-cell-autonomously to control the pathfinding of trigeminal motor axons. Thus, Pbx/Hox can function both cell-autonomously and non-cell-autonomously to direct different aspects of hindbrain motor neuron behavior.