Abstract
Transcription factors such as Scl/Tal1, Lmo2, and Runx1 are essential for the development of hematopoietic stem cells (HSCs). However, the precise mechanisms by which these factors interact to form transcriptional networks, as well as the identity of the genes downstream of these regulatory cascades, remain largely unknown. To this end, we generated an Scl(-/-) yolk sac cell line to identify candidate Scl target genes by global expression profiling after reintroduction of a TAT-Scl fusion protein. Bioinformatics analysis resulted in the identification of 9 candidate Scl target transcription factor genes, including Runx1 and Runx3. Chromatin immunoprecipitation confirmed that both Runx genes are direct targets of Scl in the fetal liver and that Runx1 is also occupied by Scl in the yolk sac. Furthermore, binding of an Scl-Lmo2-Gata2 complex was demonstrated to occur on the regions flanking the conserved E-boxes of the Runx1 loci and was shown to transactivate the Runx1 element. Together, our data provide a key component of the transcriptional network of early hematopoiesis by identifying downstream targets of Scl that can explain key aspects of the early Scl(-/-) phenotype.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Signal Transducing
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Animals
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Base Sequence
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Basic Helix-Loop-Helix Transcription Factors / deficiency
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Basic Helix-Loop-Helix Transcription Factors / genetics
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Basic Helix-Loop-Helix Transcription Factors / metabolism*
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Cell Line
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Cell Separation
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Conserved Sequence
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Core Binding Factor Alpha 2 Subunit / genetics
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Core Binding Factor Alpha 2 Subunit / metabolism*
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Core Binding Factor Alpha 3 Subunit / genetics
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Core Binding Factor Alpha 3 Subunit / metabolism*
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism
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GATA2 Transcription Factor / genetics
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GATA2 Transcription Factor / metabolism
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Gene Expression Regulation, Developmental
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Humans
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LIM Domain Proteins
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Liver / embryology*
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Liver / metabolism*
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Metalloproteins / genetics
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Metalloproteins / metabolism
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Mice
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Mice, Knockout
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Molecular Sequence Data
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Protein Binding
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Proto-Oncogene Proteins / deficiency
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Proto-Oncogene Proteins / genetics
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Proto-Oncogene Proteins / metabolism*
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Sequence Alignment
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T-Cell Acute Lymphocytic Leukemia Protein 1
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Yolk Sac / embryology*
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Yolk Sac / metabolism*
Substances
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Adaptor Proteins, Signal Transducing
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Basic Helix-Loop-Helix Transcription Factors
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Core Binding Factor Alpha 2 Subunit
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Core Binding Factor Alpha 3 Subunit
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DNA-Binding Proteins
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GATA2 Transcription Factor
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Gata2 protein, mouse
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LIM Domain Proteins
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Lmo2 protein, mouse
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Metalloproteins
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Proto-Oncogene Proteins
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Runx1 protein, mouse
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Runx3 protein, mouse
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T-Cell Acute Lymphocytic Leukemia Protein 1
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Tal1 protein, mouse