title: Netrin signaling breaks the equivalence between two identified zebrafish motoneurons revealing a new role of intermediate targets.
abstract: BACKGROUND
  We previously showed that equivalence between two identified zebrafish motoneurons is broken by interactions with identified muscle fibers that act as an intermediate target for the axons of these motoneurons. Here we investigate the molecular basis of the signaling interaction between the intermediate target and the motoneurons.
  
  
  RESULTS
  We provide evidence that Netrin 1a is an intermediate target-derived signal that causes two equivalent motoneurons to adopt distinct fates. We show that although these two motoneurons express the same Netrin receptors, their axons respond differently to Netrin 1a encountered at the intermediate target. Furthermore, we demonstrate that when Netrin 1a is knocked down, more distal intermediate targets that express other Netrins can also function to break equivalence between these motoneurons.
  
  
  CONCLUSIONS
  Our results suggest a new role for intermediate targets in breaking neuronal equivalence. The data we present reveal that signals encountered during axon pathfinding can cause equivalent neurons to adopt distinct fates. Such signals may be key in diversifying a neuronal population and leading to correct circuit formation.
authors: Institute of Neuroscience, University of Oregon, Eugene, Oregon, United States of America.
authors: Laura A
authors: LA
authors: Hale
authors: Daniel K
authors: DK
authors: Fowler
authors: Judith S
authors: JS
authors: Eisen
mesh_terms: D000818:Animals; D001369:Axons / Q000378:metabolism; D001483:Base Sequence; D002454:Cell Differentiation; D002465:Cell Movement; D002470:Cell Survival; D000075389:DCC Receptor; D005786:Gene Expression Regulation; D055785:Gene Knockdown Techniques; D009046:Motor Neurons / Q000166:cytology* / Q000378:metabolism* / Q000502:physiology; D009132:Muscles / Q000378:metabolism; D009414:Nerve Growth Factors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D000075386:Netrin Receptors; D000075388:Netrin-1; D011956:Receptors, Cell Surface / Q000378:metabolism; D013569:Synapses / Q000378:metabolism / Q000502:physiology; D025521:Tumor Suppressor Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D015027:Zebrafish / Q000378:metabolism* / Q000502:physiology; D029961:Zebrafish Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*
chemical_list: D000075389:DCC Receptor; D009414:Nerve Growth Factors; D000075386:Netrin Receptors; D011956:Receptors, Cell Surface; D025521:Tumor Suppressor Proteins; D029961:Zebrafish Proteins; C506552:dcc protein, zebrafish; C000617355:ntn1a protein, zebrafish; D000075388:Netrin-1