ZFIN ID: ZDB-PUB-060210-15
Constitutive activation of zebrafish Stat5 expands hematopoietic cell populations in vivo
Lewis, R.S., Stephenson, S.E., and Ward, A.C.
Date: 2006
Source: Experimental hematology   34(2): 179-187 (Journal)
Registered Authors: Ward, Alister C.
Keywords: none
MeSH Terms:
  • Amino Acid Substitution
  • Animals
  • Cell Line
  • Cell Lineage/physiology
  • Cell Proliferation/drug effects
  • Hematologic Diseases/genetics*
  • Hematologic Diseases/pathology
  • Hematopoietic Stem Cells/cytology
  • Hematopoietic Stem Cells/drug effects
  • Hematopoietic Stem Cells/metabolism*
  • Humans
  • In Vitro Techniques
  • Mutagenesis, Site-Directed
  • Mutation
  • Phosphorylation
  • STAT5 Transcription Factor/genetics
  • STAT5 Transcription Factor/pharmacology
  • STAT5 Transcription Factor/physiology*
  • Tyrosine/drug effects
  • Tyrosine/metabolism
  • Zebrafish
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/pharmacology
  • Zebrafish Proteins/physiology*
PubMed: 16459186 Full text @ Exp. Hematol.
OBJECTIVE: Constitutive activation of Stat5 has been observed in a variety of malignancies, particularly myeloid leukemias. To directly investigate the in vivo consequences of Stat5 perturbation, we expressed constitutively active forms in zebrafish. METHODS: We generated mutants of the zebrafish stat5.1 protein (N646H, H298R/N714F, and N714F) based on previously identified constitutively active mutants of murine Stat5a. The in vitro properties of these mutants were determined using phosphorylation-specific antibodies and luciferase reporter assays, and their in vivo effects were analyzed through microinjection of zebrafish embryos. RESULTS: Two of these stat5.1 mutants (N646H and H298R/N714F) showed increased tyrosine phosphorylation and transactivation activity compared to the wild-type protein. Expression of either mutant led to a range of hematological perturbations, which were more pronounced for the H298R/N714F mutant. Interestingly, expression of wild-type also produced generally similar phenotypes. Further analysis showed that expression of the H298R/N714F mutant led to increased numbers of early and late myeloid cells, erythrocytes, and B cells. Some nonhematopoietic developmental perturbations were also observed, but these were equally prominent with wild-type or mutant forms. CONCLUSION: These data implicate Stat5 activity as a direct critical regulator of hematological cell proliferation, suggesting a causal role for constitutively-active Stat5 in the etiology of hematological malignancies.