Treatment with Myf5-morpholino results in somite patterning and brain formation defects in zebrafish

Differentiation. 2002 Oct;70(8):447-56. doi: 10.1046/j.1432-0436.2002.700807.x.


Myf-5 is a stage-dependent transcription factor associated with somitogenesis. To study its biological functions in zebrafish, we injected the Myf5-morpholinos ZMF-MO (antisense nucleotides 28 to 52) and ZMF-OTHER (antisense nucleotides 3 to 27) into zebrafish embryos to establish a myf-5 gene knockdown. No phenotypic abnormalities were observed following injection with 0.2 ng of ZMF-MO, but defects were displayed in 2 of 118 (1.7%) surviving embryos injected with 1 ng ZMF-MO. Morphological defects became more severe with increased dosages: 105 of 270 (38.9%) surviving embryos injected with 4.5 ng of ZMF-MO displayed such abnormalities as the absence of eyes or brains in addition to the following low-dosage defects in 24 hpf embryos: longitudinal yolk sacs, incomplete epiboly coverage, abnormal and suspended tail buds, diffused somite boundaries, and head shrinkage. Similar results were observed in the 4.5 ng ZMF-OTHER injection group. However, when fish were co-injected with 4.5 ng ZMF-MO and 4.5 ng myf-5 mRNA, abnormality rates decreased from 49.6% to 5.5%. Our results show that the brain krox20 gene was down-regulated at rhombomere 3; the pax2.1 gene was completely down-regulated; myoD was expressed normally; myogenin was substantially down-regulated in whole somites; and desmin was partly inhibited in newly forming somites. Our conclusion is that zebrafish Myf-5 may play important roles in brain formation and in the convergence and extension of shield epiblasts and tail buds during early embryogenesis, in addition to its well-understood role as a muscle regulatory factor in somites.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain / embryology*
  • Brain / metabolism
  • DNA-Binding Proteins / genetics
  • Early Growth Response Protein 2
  • Genetic Markers
  • In Situ Hybridization
  • Muscle Proteins / genetics*
  • Muscle Proteins / metabolism
  • Myogenic Regulatory Factor 5
  • Oligonucleotides, Antisense / genetics
  • Oligonucleotides, Antisense / pharmacology
  • PAX2 Transcription Factor
  • Somites / metabolism*
  • Trans-Activators*
  • Transcription Factors / genetics
  • Zebrafish / embryology*
  • Zebrafish / metabolism
  • Zebrafish Proteins


  • DNA-Binding Proteins
  • Early Growth Response Protein 2
  • Genetic Markers
  • Muscle Proteins
  • Myogenic Regulatory Factor 5
  • Oligonucleotides, Antisense
  • PAX2 Transcription Factor
  • Trans-Activators
  • Transcription Factors
  • Zebrafish Proteins
  • pax2a protein, zebrafish