ZFIN ID: ZDB-PUB-110613-24
Ddx18 is essential for cell cycle progression in zebrafish hematopoietic cells and is mutated in human acute myeloid leukemia
Payne, E.M., Bolli, N., Rhodes, J., Abdel-Wahab, O.I., Levine, R., Hedvat, C.V., Stone, R., Khanna-Gupta, A., Sun, H., Kanki, J.P., Gazda, H.T., Beggs, A.H., Cotter, F.E., and Look, A.T.
Date: 2011
Source: Blood 118(4): 903-15 (Journal)
Registered Authors: Beggs, Alan H., Bolli, Niccolo, Kanki, John, Look, A. Thomas, Rhodes, Jennifer
Keywords: none
MeSH Terms:
  • Alleles
  • Animals
  • Blotting, Western
  • Cell Cycle/genetics*
  • Cell Separation
  • DEAD-box RNA Helicases/genetics*
  • DEAD-box RNA Helicases/metabolism*
  • Embryo, Nonmammalian
  • Flow Cytometry
  • Hematopoiesis/genetics*
  • Hematopoietic Stem Cells/cytology
  • Hematopoietic Stem Cells/metabolism*
  • Humans
  • In Situ Hybridization
  • Leukemia, Myeloid, Acute/genetics*
  • Mutagenesis, Site-Directed
  • Mutation
  • Myeloid Cells/cytology
  • Myeloid Cells/metabolism
  • Polymerase Chain Reaction
  • Zebrafish/metabolism*
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism*
PubMed: 21653321 Full text @ Blood
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ABSTRACT

In a zebrafish mutagenesis screen to identify genes essential for myelopoiesis, we identified an insertional allele hi1727, which disrupts the gene encoding RNA helicase dead-box 18 (Ddx18). Homozygous Ddx18 mutant embryos exhibit a profound loss of myeloid and erythroid cells along with cardiovascular abnormalities and reduced size. These mutants also display prominent apoptosis and a G1 cell-cycle arrest. Loss of p53, but not Bcl-xl overexpression, rescues myeloid cells to normal levels, suggesting that the hematopoietic defect is because of p53-dependent G1 cell-cycle arrest. We then sequenced primary samples from 262 patients with myeloid malignancies because genes essential for myelopoiesis are often mutated in human leukemias. We identified 4 nonsynonymous sequence variants (NSVs) of DDX18 in acute myeloid leukemia (AML) patient samples. RNA encoding wild-type DDX18 and 3 NSVs rescued the hematopoietic defect, indicating normal DDX18 activity. RNA encoding one mutation, DDX18-E76del, was unable to rescue hematopoiesis, and resulted in reduced myeloid cell numbers in ddx18hi1727/+ embryos, indicating this NSV likely functions as a dominant-negative allele. These studies demonstrate the use of the zebrafish as a robust in vivo system for assessing the function of genes mutated in AML, which will become increasingly important as more sequence variants are identified by next-generation resequencing technologies.

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