Abstract
The recombination-activating gene (RAG)-1 and RAG-2 are expressed specifically in immature lymphoid cells undergoing the recombination of Ag receptor genes. We studied the regulation of murine RAG-2 promoter and revealed that -41/-17 RAG-2 promoter region, which was indispensable for the RAG-2 promoter activity in B cell lines, contained binding sites for lymphoid enhancer-binding factor-1 (LEF-1), c-Myb, and Pax-5. We showed that these three transcription factors bound the promoter region in vitro and in vivo. Cotransfection assays using a human embryonic kidney cell line (293T) showed that LEF-1, c-Myb, and Pax-5 cooperatively activated the RAG-2 promoter, via their synergistic DNA binding. We also showed that LEF-1, c-Myb, and Pax-5 physically interact in the cells. Finally, we demonstrated that a dominant-negative LEF-1 protein, which lacks the binding site for beta-catenin, suppressed the RAG-2 promoter activity as well as the endogenous RAG-2 expression in a pre-B cell line (18.81). These results suggest that LEF-1/beta-catenin complex regulates the RAG-2 promoter activation in concert with c-Myb and Pax-5 in immature B cells. The link between LEF-1/beta-catenin and Wnt signaling in B lineage cells will be discussed.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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5' Untranslated Regions / metabolism
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5' Untranslated Regions / physiology
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Animals
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B-Lymphocyte Subsets / cytology
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B-Lymphocyte Subsets / immunology
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B-Lymphocyte Subsets / metabolism*
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Base Sequence
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Cell Differentiation / immunology
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Cell Line
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Cells, Cultured
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DNA-Binding Proteins / antagonists & inhibitors
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DNA-Binding Proteins / biosynthesis
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DNA-Binding Proteins / genetics*
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DNA-Binding Proteins / metabolism*
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DNA-Binding Proteins / physiology
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Drug Synergism
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Gene Expression Regulation / immunology*
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Hematopoietic Stem Cells / immunology
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Hematopoietic Stem Cells / metabolism
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Humans
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Lymphoid Enhancer-Binding Factor 1
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Macromolecular Substances
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Mice
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Nuclear Proteins
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PAX5 Transcription Factor
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Promoter Regions, Genetic / immunology*
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Protein Binding / genetics
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Protein Binding / immunology
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Proto-Oncogene Proteins c-myb / metabolism*
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Proto-Oncogene Proteins c-myb / physiology
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Transcription Factors / genetics
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Transcription Factors / metabolism*
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Transcription Factors / physiology
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Transfection
Substances
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5' Untranslated Regions
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DNA-Binding Proteins
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LEF1 protein, human
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Lef1 protein, mouse
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Lymphoid Enhancer-Binding Factor 1
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Macromolecular Substances
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Nuclear Proteins
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PAX5 Transcription Factor
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PAX5 protein, human
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Pax5 protein, mouse
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Proto-Oncogene Proteins c-myb
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RAG2 protein, human
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Rag2 protein, mouse
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Transcription Factors
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V(D)J recombination activating protein 2