Abstract
The mb-1 gene is expressed only during the early stages of B-lymphocyte differentiation. Here we show that the mb-1 proximal promoter region contains a functionally important binding site for members of the ETS family of DNA-binding proteins. We found that both the E26 virus-encoded v-ets and the myeloid/B-cell-specific factor PU.1 bind efficiently to this site in vitro. By contrast, Ets-1, the lymphocyte-specific cellular homologue of v-ets, and the related, more ubiquitously expressed Ets-2 protein interacted weakly with this binding site. DNA binding by both Ets-1 and Ets-2, however, could be increased 20- to 50-fold by deleting as few as 16 carboxyl-terminal amino acids. The inhibitory carboxyl-terminal amino acid sequence is highly conserved between Ets-1 and Ets-2 but is not present in either v-ets or PU.1. Replacement of the carboxyl-terminal amino acids of v-ets with those of Ets-1 decreased DNA binding by v-ets drastically. Cotranslation of Ets-1 transcripts encoding proteins of different lengths suggested that Ets-1 binds DNA as a monomer. Therefore, the carboxyl-terminal inhibitory domain appears to interfere directly with DNA binding and not with homodimerization. Finally, the functional relevance of ETS factor binding to the mb-1 promoter site was evidenced by the stimulation of transcription through this site by a v-myb-v-ets fusion protein. Together, these data suggest that one or more ETS family factors are involved in the regulation of mb-1 gene expression.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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B-Lymphocytes / cytology
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B-Lymphocytes / physiology
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Base Sequence
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Binding Sites
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Cell Differentiation / genetics
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Chloramphenicol O-Acetyltransferase / genetics
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Chloramphenicol O-Acetyltransferase / isolation & purification
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Chloramphenicol O-Acetyltransferase / metabolism
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DNA-Binding Proteins / metabolism
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Gene Expression
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Molecular Sequence Data
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Multigene Family
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Mutagenesis, Site-Directed
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Oligodeoxyribonucleotides
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Oncogenes
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Promoter Regions, Genetic*
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Protein Biosynthesis
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Protein-Tyrosine Kinases / genetics
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Protein-Tyrosine Kinases / metabolism
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Proto-Oncogene Protein c-ets-1
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Proto-Oncogene Protein c-ets-2
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Proto-Oncogene Proteins / genetics
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Proto-Oncogene Proteins / isolation & purification
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Proto-Oncogene Proteins / metabolism*
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Proto-Oncogene Proteins c-ets
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Proto-Oncogenes
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Recombinant Fusion Proteins / isolation & purification
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Recombinant Fusion Proteins / metabolism
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Repressor Proteins*
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Restriction Mapping
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Retroviridae Proteins, Oncogenic / genetics
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Retroviridae Proteins, Oncogenic / isolation & purification
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Retroviridae Proteins, Oncogenic / metabolism*
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Trans-Activators*
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Transcription Factors*
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Transcription, Genetic
Substances
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DNA-Binding Proteins
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ERF protein, human
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ETS1 protein, human
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Oligodeoxyribonucleotides
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Proto-Oncogene Protein c-ets-1
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Proto-Oncogene Protein c-ets-2
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Proto-Oncogene Proteins
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Proto-Oncogene Proteins c-ets
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Recombinant Fusion Proteins
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Repressor Proteins
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Retroviridae Proteins, Oncogenic
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Trans-Activators
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Transcription Factors
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oncogene proteins v-ets
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Chloramphenicol O-Acetyltransferase
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Protein-Tyrosine Kinases