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Isolation of Translating Ribosomes Containing Peptidyl-tRNAs for Functional and Structural Analyses
Published on: February 25, 2011
Enhanced ribosome frameshifting in stationary phase cells
Z Barak1, J Gallant, D Lindsley
1Department of Life Sciences, Ben Gurion University of the Negev, Beersheva, Israel.
Journal of Molecular Biology
|October 25, 1996
Summary
Bacterial growth phase significantly impacts gene translation. During stationary phase, Escherichia coli dramatically increases synthesis of a frameshift-dependent lacZ gene, enhancing enzyme activity.
Area of Science:
- Molecular Biology
- Microbial Genetics
- Bacterial Physiology
Background:
- Gene expression regulation is crucial for bacterial adaptation.
- Translational control mechanisms, including frameshifting, influence protein synthesis.
- Escherichia coli growth phases exhibit distinct physiological states affecting gene expression.
Purpose of the Study:
- To investigate the influence of Escherichia coli growth phase on the translation of a plasmid-borne lacZ gene.
- To determine the impact of a required leftward frameshift on enzyme synthesis rates.
- To analyze the underlying mechanisms of increased enzyme production in different growth phases.
Main Methods:
- Utilized a plasmid-borne lacZ reporter system requiring a specific frameshift for active enzyme synthesis.
- Compared enzyme synthesis rates and specific activity across different growth phases (log, stationary) in Escherichia coli.
- Employed protein sequence analysis to confirm frameshifting versus termination-reinitiation.
Main Results:
- Enzyme synthesis rate for the frameshift-dependent lacZ gene was very low during the log phase.
- A significant increase (two orders of magnitude) in enzyme synthesis occurred during late log and early stationary phases.
- Protein analysis confirmed increased synthesis was due to frameshifting at the UUC AAG sequence, not reinitiation.
Conclusions:
- Bacterial growth phase is a critical regulator of frameshift efficiency and translation.
- Stationary phase promotes high-efficiency frameshifting, leading to substantial increases in reporter gene expression.
- The UUC AAG sequence represents an intrinsically shifty site whose frameshift efficiency is modulated by growth phase.
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