GATA-2/estrogen receptor chimera regulates cytokine-dependent growth of hematopoietic cells through accumulation of p21(WAF1) and p27(Kip1) proteins.
GATA-2 is considered to be essential for the development, maintenance, and function of hematopoietic stem cells (HSCs). However, it was also reported that GATA-2 inhibits the growth of HSCs. To examine the role of GATA-2 in the growth of hematopoietic cells, we introduced an estradiol-inducible form of GATA-2 (GATA-2/estrogen receptor [ER]) into interleukin 3 (IL-3)-dependent cell lines, Ba/F3, 32D, and FDC-P1. Estradiol-induced GATA-2 suppressed c-myc mRNA expression and inhibited IL-3-dependent growth in these clones. As for this mechanism, GATA-2 was found to inhibit ubiquitin/proteasome-dependent degradation of p21(WAF1) and p27(Kip1) and to induce their accumulation by repressing the expression of Skp2 and Cul1, both of which are components of the ubiquitin ligase for p21(WAF1) and p27(Kip1). Overexpression of c-myc restored the expression of Skp2 and Cul1 mRNA, reduced the amounts of p21(WAF1) and p27(Kip1) proteins, and canceled GATA-2-induced growth suppression, suggesting that down-regulation of c-myc expression may be primarily responsible for GATA-2-induced growth suppression. Next, we transduced retrovirus containing GATA-2/ER into murine bone marrow mononuclear cells (MNCs) and stem/progenitor (Sca-1(+)Lin(-)) cells. GATA-2/ER suppressed cytokine-dependent growth of MNCs and Sca-1(+)Lin(-) cells by about 70%, which was also accompanied by the reduced expression of c-myc, Skp2, and Cul1 mRNA and the accumulation of p21(WAF1) and p27(Kip1) proteins. In addition, the amount of GATA-2 protein was found to decline in hematopoietic stem/progenitor cells that were promoted to enter cell cycle by the stimulation with cytokines. These results suggest that GATA-2 may regulate expression levels of p21(WAF1) and p27(Kip1), thereby contributing to the quiescence of hematopoietic stem/progenitor cells.
Ezoe
Sachiko
S
Department of Hematology/Oncology and Molecular Oncology, Osaka University Graduate School of Medicine, 2-2, Yamada-oka, Suita, Osaka, Japan.
Matsumura
Itaru
I
Nakata
Soichi
S
Gale
Karin
K
Ishihara
Katsuhiko
K
Minegishi
Naoko
N
Machii
Takashi
T
Kitamura
Toshio
T
Yamamoto
Masayuki
M
Enver
Tariq
T
Kanakura
Yuzuru
Y
D000818:Animals; D001854:Bone Marrow Cells / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000187:drug effects / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D044842:Cullin Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D050760:Cyclin-Dependent Kinase Inhibitor p27; D016213:Cyclins / Q000187:drug effects / Q000378:metabolism; D016207:Cytokines; D004268:DNA-Binding Proteins / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D050989:GATA2 Transcription Factor; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects; D006801:Humans; D051379:Mice; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics / Q000502:physiology; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D011960:Receptors, Estrogen / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics; D044786:S-Phase Kinase-Associated Proteins; D014157:Transcription Factors / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D014162:Transfection; D025521:Tumor Suppressor Proteins / Q000187:drug effects / Q000378:metabolism
C493956:CDKN1A protein, human; C493957:Cdkn1a protein, mouse; C493961:Cdkn1b protein, mouse; D018797:Cell Cycle Proteins; C100318:Cullin 1; D044842:Cullin Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D016207:Cytokines; D004268:DNA-Binding Proteins; D050989:GATA2 Transcription Factor; C494711:GATA2 protein, human; C494712:Gata2 protein, mouse; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D011960:Receptors, Estrogen; D011993:Recombinant Fusion Proteins; D044786:S-Phase Kinase-Associated Proteins; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27