Abstract
GATA-1 and PU.1 are essential hematopoietic transcription factors that control erythromegakaryocytic and myelolymphoid differentiation, respectively. These proteins antagonize each other through direct physical interaction to repress alternate lineage programs. We used immortalized Gata1(-) erythromegakaryocytic progenitor cells to study how PU.1/Sfpi1 expression is regulated by GATA-1 and GATA-2, a related factor that is normally expressed at earlier stages of hematopoiesis. Both GATA factors bind the PU.1/Sfpi1 gene at 2 highly conserved regions. In the absence of GATA-1, GATA-2 binding is associated with an undifferentiated state, intermediate level PU.1/Sfpi1 expression, and low-level expression of its downstream myeloid target genes. Restoration of GATA-1 function induces erythromegakaryocytic differentiation. Concomitantly, GATA-1 replaces GATA-2 at the PU.1/Sfpi1 locus and PU.1/Sfpi1 expression is extinguished. In contrast, when GATA-1 is not present, shRNA knockdown of GATA-2 increases PU.1/Sfpi1 expression by 3-fold and reprograms the cells to become macrophages. Our findings indicate that GATA factors act sequentially to regulate lineage determination during hematopoiesis, in part by exerting variable repressive effects at the PU.1/Sfpi1 locus.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Animals
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Cell Lineage
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Cells, Cultured / drug effects
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Cells, Cultured / metabolism
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Cytokines / pharmacology
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Erythropoiesis / genetics*
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GATA1 Transcription Factor / deficiency
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GATA1 Transcription Factor / genetics
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GATA1 Transcription Factor / physiology*
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GATA2 Transcription Factor / physiology*
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Gene Expression Regulation / physiology*
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Gene Knockdown Techniques
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Hematopoietic Stem Cells / cytology*
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Hematopoietic Stem Cells / metabolism
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Macrophages / cytology
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Mice
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Proto-Oncogene Proteins / antagonists & inhibitors
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Proto-Oncogene Proteins / biosynthesis*
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Proto-Oncogene Proteins / genetics
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Proto-Oncogene Proteins / physiology
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RNA, Small Interfering / pharmacology
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Recombinant Fusion Proteins / physiology
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Repressor Proteins / biosynthesis*
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Repressor Proteins / genetics
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Repressor Proteins / physiology
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Thrombopoiesis / genetics*
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Trans-Activators / antagonists & inhibitors
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Trans-Activators / biosynthesis*
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Trans-Activators / genetics
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Trans-Activators / physiology
Substances
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Cytokines
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GATA1 Transcription Factor
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GATA2 Transcription Factor
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Gata1 protein, mouse
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Gata2 protein, mouse
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Proto-Oncogene Proteins
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RNA, Small Interfering
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Recombinant Fusion Proteins
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Repressor Proteins
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Trans-Activators
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proto-oncogene protein Spi-1