ZFIN ID: ZDB-PUB-121012-22
Maternal pak4 Expression is Required for Primitive Myelopoiesis in Zebrafish
Law, S.H., and Sargent, T.D.
Date: 2013
Source: Mechanisms of Development   130(2-3): 181-194 (Journal)
Registered Authors: Sargent, Tom
Keywords: p21-activated kinase 4, maternal, myelopoiesis, granulocyte, leukocyte, actin
MeSH Terms:
  • Actin Cytoskeleton/metabolism
  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Female
  • Gene Knockdown Techniques
  • Hematopoiesis/genetics
  • Morpholinos/genetics
  • Myelopoiesis/genetics*
  • Organ Specificity
  • Protein Biosynthesis
  • RNA, Messenger, Stored/genetics
  • RNA, Messenger, Stored/metabolism
  • Transcription, Genetic
  • Zebrafish/embryology*
  • Zebrafish/metabolism
  • Zebrafish Proteins/genetics*
  • Zebrafish Proteins/metabolism
  • Zygote/metabolism
  • p21-Activated Kinases/genetics*
  • p21-Activated Kinases/metabolism
PubMed: 23032194 Full text @ Mech. Dev.

Transcripts of pak4, the zebrafish ortholog of p21-activated kinase 4 (PAK4), are most abundant in the egg and fall to low levels by the end of gastrulation, after which expression is essentially ubiquitous. Translation of maternal mRNA into pak4 protein is first detectable at high stage (3.3 hpf). Splice-blocking morpholino oligonucleotides (MOs) were used to prevent zygotic pak4 expression. This had no discernable effect on development through larval stages. In contrast, a translation-blocking MO, alone or in combination with the splice MOs, resulted in a complex lethal phenotype. In addition to disrupted somite development and other morphogenetic abnormalities, the knockdown of maternal pak4 expression led to alterations in regulatory gene expression in the primitive hematopoietic domains, leading to deficiencies in granulocyte and leukocyte lineages. At least some of the effects of pak4 knockdown on gene expression could be mimicked by treatment with actin depolymerization agents, suggesting a mechanistic link between regulation of microfilament dynamics by pak4 and regulation of gene expression in primitive myeloid cell differentiation.