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Expression of peptide chain release factor 2 requires high-efficiency frameshift.
Nature
|July 17, 1986
Summary
Escherichia coli release factor 2 (RF2) gene expression is autogenously regulated. A UGA stop codon within the RF2 gene coding sequence triggers a +1 frameshift, ensuring controlled production of this essential protein synthesis termination factor.
Area of Science:
- Molecular Biology
- Genetics
- Protein Synthesis
Background:
- Peptide chain release factors (RF1 and RF2) terminate polypeptide biosynthesis in Escherichia coli.
- RF1 recognizes UAG/UAA codons, while RF2 recognizes UGA/UAA codons.
- Low concentrations of release factors suggest tight regulation of their expression.
Purpose of the Study:
- To investigate the autogenous regulation mechanism of RF2 in Escherichia coli.
- To confirm the role of an in-frame UGA stop codon in RF2 gene expression control.
Main Methods:
- In vitro experiments to assess RF2 autogenous regulation.
- Construction and analysis of RF2-lacZ gene fusions.
- Deletion analysis of the in-frame stop codon in the RF2 gene.
Main Results:
- In vitro results support the autogenous regulation of RF2.
- RF2-lacZ fusions demonstrated premature termination at the in-frame stop codon.
- Deletion of the stop codon resulted in overproduction of the RF2-LacZ fusion protein.
- Frameshifting at the premature termination codon occurs at a high rate of 50%.
Conclusions:
- Autogenous regulation of RF2 occurs, at least partially, through premature termination at an in-frame stop codon.
- This regulatory mechanism ensures controlled synthesis of RF2.
- The high frameshifting rate highlights the efficiency of this regulatory process.