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Updated: Jun 27, 2026
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Genome-wide Purification of Extrachromosomal Circular DNA from Eukaryotic Cells
Published on: April 4, 2016
Recombination within the yeast plasmid 2mu circle is site-specific
Cell
|May 1, 1982
Summary
The yeast 2-micron (2mu) circle plasmid utilizes a FLP recombinase system for site-specific recombination between its inverted repeats. This process is crucial for plasmid stability and occurs at a defined recombination site, even at low levels during meiosis without FLP.
Area of Science:
- Molecular Biology
- Yeast Genetics
- Recombination Mechanisms
Background:
- The 2-micron (2mu) circle is a high-copy number yeast plasmid.
- It possesses a unique site-specific recombination system involving inverted repeat regions.
- This system requires the FLP recombinase enzyme for efficient function.
Purpose of the Study:
- To precisely map the recombination site within the 2mu circle repeats.
- To identify the minimal sequence required for FLP-mediated recombination.
- To determine if other 2mu circle genes are necessary for this process.
- To develop a sensitive assay for detecting 2mu circle recombination.
Main Methods:
- Analysis of recombination products from plasmids with insertions/deletions within repeat regions.
- Site-directed mutagenesis of the 2mu circle genome.
- Development and application of a sensitive recombination assay.
- Examination of recombination during yeast meiosis.
Main Results:
- FLP-mediated recombination occurs at a specific site within the 2mu circle repeats, limited to a sequence under 65 bp.
- The FLP gene product is the only essential 2mu circle gene for site-specific recombination.
- A sensitive assay detected low-level recombination between repeats even without FLP during meiosis.
Conclusions:
- The 2mu circle recombination site is highly specific and requires FLP recombinase.
- FLP is the sole essential gene product for efficient site-specific recombination.
- Non-FLP-mediated recombination can occur at a low frequency during meiosis, suggesting alternative mechanisms or basal activity.
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