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Published on: March 1, 2019
In-frame overlapping genes: the challenges for regulating gene expression.
Jae-Sung Yu1, Robert J Kokoska, Vanessa Khemici
1Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA.
Molecular Microbiology
|January 24, 2007
Summary
In-frame overlapping genes in phage f1 require translational controls for proper regulation. Ribosome interference limits expression of gene X, necessitating further downregulation for cell survival.
Area of Science:
- Molecular Biology
- Genetics
- Virology
Background:
- In-frame overlapping genes allow multiple proteins from a single gene, common in phage, plasmid, and bacterial genomes.
- While preventing recombination, these arrangements pose regulatory challenges.
Purpose of the Study:
- To investigate translational controls regulating in-frame overlapping genes II and X in filamentous phage f1.
- To understand how relative protein levels of pII and pX are maintained for phage DNA replication.
Main Methods:
- Progressive deletion into the gene II initiator region to alter gene II translation.
- Site-directed mutagenesis and nuclease mapping to analyze RNA secondary structures.
- Amber codon suppression efficiency to quantify translational interference.
Main Results:
- Lowering gene II translation increased gene X translation, indicating ribosome interference.
- Gene X translation is limited by ribosome progression on gene II mRNA.
- RNA secondary structures sequester the gene X initiation site, reducing its translation.
Conclusions:
- Translational control mechanisms, including ribosome interference and RNA structures, are crucial for regulating in-frame overlapping genes.
- Downregulation of gene X expression is necessary to maintain tolerable pX levels relative to pII.
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