Gene expression profiling identifies HOXB4 as a direct downstream target of GATA-2 in human CD34+ hematopoietic cells

PLoS One. 2012;7(9):e40959. doi: 10.1371/journal.pone.0040959. Epub 2012 Sep 24.

Abstract

Aplastic anemia is characterized by a reduced hematopoietic stem cell number. Although GATA-2 expression was reported to be decreased in CD34-positive cells in aplastic anemia, many questions remain regarding the intrinsic characteristics of hematopoietic stem cells in this disease. In this study, we identified HOXB4 as a downstream target of GATA-2 based on expression profiling with human cord blood-derived CD34-positive cells infected with control or GATA-2 lentiviral shRNA. To confirm the functional link between GATA-2 and HOXB4, we conducted GATA-2 gain-of-function and loss-of-function experiments, and HOXB4 promoter analysis, including luciferase assay, in vitro DNA binding analysis and quantitative ChIP analysis, using K562 and CD34-positive cells. The analyses suggested that GATA-2 directly regulates HOXB4 expression through the GATA sequence in the promoter region. Furthermore, we assessed GATA-2 and HOXB4 expression in CD34-positive cells from patients with aplastic anemia (n = 10) and idiopathic thrombocytopenic purpura (n = 13), and demonstrated that the expression levels of HOXB4 and GATA-2 were correlated in these populations (r = 0.6573, p<0.01). Our results suggested that GATA-2 directly regulates HOXB4 expression in hematopoietic stem cells, which may play an important role in the development and/or progression of aplastic anemia.

MeSH terms

  • Anemia, Aplastic / genetics
  • Anemia, Aplastic / metabolism
  • Antigens, CD34 / metabolism*
  • Base Sequence
  • GATA2 Transcription Factor / genetics
  • GATA2 Transcription Factor / metabolism*
  • Gene Expression Profiling*
  • Gene Expression Regulation
  • Hematopoietic Stem Cells / metabolism*
  • Homeodomain Proteins / genetics*
  • Homeodomain Proteins / metabolism
  • Humans
  • K562 Cells
  • Molecular Sequence Data
  • Promoter Regions, Genetic
  • Protein Binding
  • Purpura, Thrombocytopenic, Idiopathic / genetics
  • Purpura, Thrombocytopenic, Idiopathic / metabolism
  • RNA Interference
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism
  • Transcription, Genetic

Substances

  • Antigens, CD34
  • GATA2 Transcription Factor
  • HOXB4 protein, human
  • Homeodomain Proteins
  • Transcription Factors

Grant support

The authors have no support or funding to report.