Structural studies of lacUV5-RNA polymerase interactions in vitro. Ethylation interference and missing nucleoside
1Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706, USA.
The Journal of Biological Chemistry
|March 14, 2000
Summary
Investigating Escherichia coli RNA polymerase interactions with the lacUV5 promoter using chemical methods revealed new binding sites. Modifications near the transcription start site were found to enhance RNA polymerase binding.
Area of Science:
- Molecular Biology
- Biochemistry
- Genetics
Background:
- Escherichia coli RNA polymerase interactions with promoter DNA are crucial for transcription initiation.
- The lacUV5 promoter is a well-studied model system for investigating these interactions.
Purpose of the Study:
- To expand knowledge of RNA polymerase-promoter DNA interactions using chemical interference methods.
- To identify specific DNA modifications that affect RNA polymerase binding to the lacUV5 promoter.
Main Methods:
- Utilized two chemical interference protocols: phosphate ethylation and missing nucleoside analysis.
- Applied these methods to probe interactions at various positions within the lacUV5 promoter DNA sequence.
Main Results:
- Identified additional phosphate groups, particularly on the template strand at the start site, that perturb RNA polymerase binding when ethylated.
- Discovered specific non-template strand positions (-37 to -34) where nucleoside loss decreases binding.
- Found that certain ethylation and nucleoside loss positions, especially near the transcription start site, enhance RNA polymerase binding.
Conclusions:
- Chemical interference methods provide valuable insights into RNA polymerase-promoter DNA interactions.
- Specific DNA modifications can either inhibit or enhance RNA polymerase binding, highlighting the complexity of transcription initiation.
- The study identified novel interaction points and regulatory mechanisms at the lacUV5 promoter.
