ZFIN ID: ZDB-PUB-070625-7
The role of jak2a in zebrafish hematopoiesis
Ma, A.C., Ward, A.C., Liang, R., and Leung, A.Y.
Date: 2007
Source: Blood   110(6): 1824-1830 (Journal)
Registered Authors: Leung, Anskar
Keywords: none
MeSH Terms:
  • Animals
  • Animals, Genetically Modified
  • Cell Division
  • Cell Lineage
  • Embryo, Nonmammalian/physiology*
  • Enzyme Activation
  • Erythroid Precursor Cells/metabolism
  • Gene Expression Profiling
  • Gene Expression Regulation, Developmental*
  • Glycoproteins/metabolism
  • Hematopoiesis*
  • Intercellular Signaling Peptides and Proteins/metabolism
  • Janus Kinase 2/genetics
  • Janus Kinase 2/physiology*
  • Neovascularization, Physiologic
  • Oligonucleotide Array Sequence Analysis
  • Phosphorylation
  • STAT5 Transcription Factor/metabolism
  • Signal Transduction
  • Zebrafish/embryology*
  • Zebrafish/genetics
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism*
PubMed: 17545503 Full text @ Blood
Janus kinase 2 (Jak2) transduces signals from hematopoietic cytokines and a gain-of-function mutation (Jak2(V617F)) is associated with myeloproliferative diseases particularly polycythemia vera. In this study, we examined the role of jak2a in zebrafish embryos in knock-down and over-expression studies using morpholinos (MOs) targeting the 5'untranslated region (UTR) (jak2a(UTR)-MO) and splice-site junction (jak2a(SS)-MO) of jak2a, a Jak inhibitor AG490 and a constitutive-active form of jak2a (jak2a(ca)). At 18 and 24 hours-post-fertilization (hpf), jak2a is expressed predominantly in the intermediate cell mass (ICM, site of primitive hematopoiesis) of wild-type and chordin morphant embryos (characterized by expansion of ICM). Both jak2a MOs and AG490 reduced gata1(+) (erythroid) cells in Tg(gata1:GFP) embryos, stat5 phosphorylation and gene expression associated with early progenitors (scl and lmo2), erythroid (gata1, alphahe1 and betahe1) and myeloid [spi1 (early) and mpo (late)] lineages. The chordin morphant is associated with increased stat5 phosphorylation and both jak2a MOs and treatment with AG490 significantly ameliorated ICM expansion and hematopoietic gene up-regulation in these embryos. Injection of plasmid encoding jak2a(ca) significantly increased erythropoiesis and expression of gata1, alphahe1 and betahe1, spi1, mpo and l-plastin. In conclusion, zebrafish jak2a is involved in primitive hematopoiesis under normal and deregulated conditions.