A GATA-2/estrogen receptor chimera functions as a ligand-dependent negative regulator of self-renewal.
The transcription factor GATA-2 is expressed in hematopoietic stem and progenitor cells and is functionally implicated in their survival and proliferation. We have used estrogen and tamoxifen-inducible forms of GATA-2 to modulate the levels of GATA-2 in the IL-3-dependent multipotential hematopoietic progenitor cell model FDCP mix. Ligand-dependent induction of exogenous GATA-2 activity did not rescue cells deprived of IL-3 from apoptosis. However, induction of GATA-2 activity in cells cultured in IL-3 blocked factor-dependent self-renewal but not factor-dependent survival: Cells undergo cell cycle arrest and cease proliferating but do not apoptose. This was accompanied by differentiation down the monocytic and granulocytic pathways. Differentiation occurred in the presence of IL-3 and did not require addition of exogenous differentiation growth factors such as G-CSF or GM-CSF normally required to induce granulomonocytic differentiation of FDCP-mix cells. Conversely, EPO-dependent erythroid differentiation was inhibited by GATA-2 activation. These biological effects were obtained with levels of exogenous GATA-2 representing less than twofold increases over endogenous GATA-2 levels and were not observed in cells overexpressing GATA-1/ER. Similar effects on proliferation and differentiation were also observed in primary progenitor cells, freshly isolated from murine bone marrow and transduced with a GATA-2/ER-containing retrovirus. Taken together, these data suggest that threshold activities of GATA-2 in hematopoietic progenitor cells are a critical determinant in influencing self-renewal versus differentiation outcomes.
Heyworth
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C
Cancer Research Campaign (CRC) Section of Hematopoietic Cell and Gene Therapeutics, Paterson Institute for Cancer Research, Christie Hospital National Health Service Trust, Manchester M20 4BX, UK.
Gale
K
K
Dexter
M
M
May
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G
Enver
T
T
D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation / Q000235:genetics; D002460:Cell Line; D019070:Cell Lineage; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; D050989:GATA2 Transcription Factor; D018507:Gene Expression Regulation, Developmental; D008024:Ligands; D051379:Mice; D011960:Receptors, Estrogen / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D017931:DNA Primers; D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; D050989:GATA2 Transcription Factor; C494689:Gata1 protein, mouse; C494712:Gata2 protein, mouse; D008024:Ligands; D011960:Receptors, Estrogen; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors