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Promoter Capture Hi-C: High-resolution, Genome-wide Profiling of Promoter Interactions
Published on: June 28, 2018
Promoter recognition and discrimination by EsigmaS RNA polymerase.
1Department of Bacteriology, University of Wisconsin, Madison WI 53706, USA.
Molecular Microbiology
|December 12, 2001
Summary
The study reveals that Escherichia coli sigmaS (EsigmaS) and sigma70 (Esigma70) RNA polymerase holoenzymes recognize promoters differently. Instead of distinct consensus sequences, they tolerate varying deviations from promoter elements for selective DNA binding.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Escherichia coli utilizes sigmaS (EsigmaS) and sigma70 (Esigma70) RNA polymerase holoenzymes for transcription.
- While some promoter overlap exists between EsigmaS and Esigma70, the specific DNA recognition elements for EsigmaS are not fully understood.
Purpose of the Study:
- To define the DNA sequences preferentially recognized by EsigmaS in vitro.
- To elucidate the mechanism of promoter selectivity employed by EsigmaS.
Main Methods:
- In vitro selection and enrichment of DNA sequences binding EsigmaS from a random pool.
- Genetic and biochemical analyses to compare EsigmaS and Esigma70 promoter recognition.
Main Results:
- Sequences selected by EsigmaS surprisingly contained consensus elements (-10 and -35 hexamers) typically recognized by Esigma70.
- EsigmaS and Esigma70 do not achieve specificity through 'best fit' to distinct consensus promoter hexamers.
- Promoter discrimination is achieved by EsigmaS and Esigma70 tolerating different deviations from consensus sequences.
Conclusions:
- EsigmaS-specific promoter recognition differs from the 'best fit' model seen with other holoenzymes.
- Promoter selectivity by EsigmaS and Esigma70 involves differential tolerance of sequence variations from consensus.
- This represents an alternative strategy for promoter selectivity in bacteria.
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