Hedgehog signaling is required for primary motoneuron induction in zebrafish

K. E. Lewis, J. S. Eisen

Research output: Contribution to journalArticlepeer-review

99 Scopus citations


Sonic hedgehog (Shh) is crucial for motoneuron development in chick and mouse. However, zebrafish embryos homozygous for a deletion of the shh locus have normal numbers of motoneurons, raising the possibility that zebrafish motoneurons may be specified differently. Unlike other vertebrates, zebrafish express three hh genes in the embryonic midline: shh, echidna hedgehog (ehh) and tiggywinkle hedgehog (twhh). Therefore, it is possible that Twhh and Ehh are sufficient for motoneuron formation in the absence of Shh. To test this hypothesis we have eliminated, or severely reduced, all three Hh signals using mutations that directly or indirectly reduce Hh signaling and antisense morpholinos. Our analysis shows that Hh signals are required for zebrafish motoneuron induction. However, each of the three zebrafish Hhs is individually dispensable for motoneuron development because the other two can compensate for its loss. Our results also suggest that Twhh and Shh are more important for motoneuron development than Ehh.

Original languageEnglish (US)
Pages (from-to)3485-3495
Number of pages11
Issue number18
StatePublished - 2001
Externally publishedYes


  • Floor plate
  • Hh
  • Morpholino
  • Motoneuron
  • Smoothened
  • Spinal cord patterning
  • Ventral neural tube
  • cyc
  • ehh
  • flh
  • shh
  • smu
  • syu
  • twhh

ASJC Scopus subject areas

  • Molecular Biology
  • Developmental Biology


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