The zebrafish detour gene is essential for cranial but not spinal motor neuron induction.
The zebrafish detour (dtr) mutation generates a novel neuronal phenotype. In dtr mutants, most cranial motor neurons, especially the branchiomotor, are missing. However, spinal motor neurons are generated normally. The loss of cranial motor neurons is not due to aberrant hindbrain patterning, failure of neurogenesis, increased cell death or absence of hh expression. Furthermore, activation of the Hh pathway, which normally induces branchiomotor neurons, fails to induce motor neurons in the dtr hindbrain. Despite this, not all Hh-mediated regulation of hindbrain development is abolished since the regulation of a neural gene by Hh is intact in the dtr hindbrain. Finally, dtr can function cell autonomously to induce branchiomotor neurons. These results suggest that detour encodes a component of the Hh signaling pathway that is essential for the induction of motor neurons in the hindbrain but not in the spinal cord and that dtr function is required for the induction of only a subset of Hh-mediated events in the hindbrain.
Chandrasekhar
A
A
Department of Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA. anandc@missouri.edu
Schauerte
H E
HE
Haffter
P
P
Kuwada
J Y
JY
D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D015816:Cell Adhesion Molecules, Neuronal / Q000235:genetics / Q000378:metabolism; D058969:Contactin 2; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism; D004625:Embryo, Nonmammalian; D004627:Embryonic Induction / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D053823:Hedgehog Proteins; D009046:Motor Neurons / Q000502:physiology*; D009154:Mutation; D009414:Nerve Growth Factors / Q000235:genetics / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D000075388:Netrin-1; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D012249:Rhombencephalon / Q000196:embryology* / Q000378:metabolism; D015398:Signal Transduction; D013131:Spine / Q000196:embryology / Q000294:innervation*; D015534:Trans-Activators; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D015027:Zebrafish / Q000196:embryology / Q000235:genetics*; D029961:Zebrafish Proteins
D051792:Basic Helix-Loop-Helix Proteins; D015816:Cell Adhesion Molecules, Neuronal; D058969:Contactin 2; D017868:Cyclic AMP-Dependent Protein Kinases; D053823:Hedgehog Proteins; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D000075388:Netrin-1; D011506:Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D029961:Zebrafish Proteins; C486337:neurog1 protein, zebrafish