The serine-threonine protein kinase PAK4 is dispensable in zebrafish: identification of a morpholino-generated pseudophenotype

PLoS One. 2014 Jun 19;9(6):e100268. doi: 10.1371/journal.pone.0100268. eCollection 2014.


TALEN-based inactivation of the zebrafish pak4 gene resulted in embryos and adult fish that appear normal and fertile. This is in contrast to our previously published studies which were based on the use of antisense morpholino oligonucleotides (MOs). We have excluded potential explanations such as gene duplication, alternate splicing, cryptic initiation of translation, and translation-independent RNA function. Our conclusion is that pak4 is dispensable in zebrafish, and that even when corroborated by robust controls, such as RNA rescue, MOs may elicit misleading pseudophenotypes that do not correspond to results obtained by genetic mutations, and should thus be used with caution.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Alleles
  • Animals
  • Base Sequence
  • Endonucleases / metabolism
  • Female
  • Gene Knockout Techniques
  • INDEL Mutation / genetics
  • Male
  • Molecular Sequence Data
  • Morpholinos / pharmacology*
  • Mutation / genetics
  • Phenotype
  • RNA / genetics
  • RNA / metabolism
  • Stress, Physiological / drug effects
  • Stress, Physiological / genetics
  • Trans-Activators / metabolism
  • Zebrafish / embryology
  • Zebrafish / metabolism*
  • Zebrafish Proteins / genetics
  • Zebrafish Proteins / metabolism*
  • p21-Activated Kinases / genetics
  • p21-Activated Kinases / metabolism*


  • Morpholinos
  • Trans-Activators
  • Zebrafish Proteins
  • RNA
  • PAK4 protein, zebrafish
  • p21-Activated Kinases
  • Endonucleases