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Sequences required for antitermination by phage 82 Q protein
1Section of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, NY 14853.
Journal of Molecular Biology
|December 5, 1989
Summary
Bacteriophage Q proteins bind to specific sites near promoters, pausing RNA polymerase to ensure proper gene expression. Deletion analysis reveals key sequences for this pausing and Q protein function.
Area of Science:
- Molecular Biology
- Virology
- Genetics
Background:
- Bacteriophages lambda and 82 utilize gene Q antiterminator proteins.
- These proteins interact with RNA polymerase at specific sites (qut) near promoters.
- RNA polymerase pausing is a critical step in this process.
Purpose of the Study:
- To investigate the role of the phage 82 qut site in RNA polymerase pausing and Q protein function.
- To identify specific sequences within the qut site essential for Q protein activity.
- To elucidate the mechanism of Q protein-mediated antitermination.
Main Methods:
- Deletion analysis of the phage 82 qut site.
- In vivo and in vitro functional assays of Q protein activity.
- Investigation of NusA protein's role in antitermination.
Main Results:
- Deletion analysis identified sequences required for pausing and Q function.
- Part of the qut site is located in the non-transcribed promoter region.
- NusA protein is essential for Q82 activity on certain qut82 deletions.
- qut82 is specifically active on RNA polymerase initiating at the associated promoter.
Conclusions:
- The phage 82 qut site contains essential sequences for RNA polymerase pausing and Q antiterminator protein function.
- The interaction between Q protein, qut site, and RNA polymerase is promoter-specific.
- NusA protein plays a regulatory role in Q-mediated antitermination.