Abstract
Escherichia coli MelR protein is a transcription activator that is essential for melibiose-dependent expression of the melAB genes. We have used chromatin immunoprecipitation to study the binding of MelR and RNA polymerase to the melAB promoter in vivo. Our results show that MelR is associated with promoter DNA, both in the absence and presence of the inducer melibiose. In contrast, RNA polymerase is recruited to the melAB promoter only in the presence of inducer. The MelR DK261 positive control mutant binds to the melAB promoter but cannot recruit RNA polymerase. Further analysis of immunoprecipitated DNA, by using an Affymetrix GeneChip array, showed that the melAB promoter is the major, if not the sole, target in E. coli for MelR. This was confirmed by a transcriptomics experiment to analyze RNA in cells either with or without melR.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Chromatin
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism*
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DNA-Directed RNA Polymerases / genetics
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DNA-Directed RNA Polymerases / metabolism
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Escherichia coli / genetics
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Escherichia coli / metabolism*
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Escherichia coli Proteins / genetics
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Escherichia coli Proteins / metabolism*
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Gene Expression Profiling
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Gene Expression Regulation, Bacterial*
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Genome, Bacterial*
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Melibiose / metabolism*
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Oligonucleotide Array Sequence Analysis / methods*
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Precipitin Tests / methods*
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Promoter Regions, Genetic
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Protein Binding
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Symporters / genetics
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Symporters / metabolism
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Trans-Activators / genetics
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Trans-Activators / metabolism*
Substances
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Chromatin
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DNA-Binding Proteins
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Escherichia coli Proteins
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MelR protein, E coli
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Symporters
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Trans-Activators
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melibiose permease
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Melibiose
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DNA-Directed RNA Polymerases