Related Experiment Video
Updated: Aug 9, 2026
10:57
Growth-based Determination and Biochemical Confirmation of Genetic Requirements for Protein Degradation in Saccharomyces cerevisiae
Published on: February 16, 2015
Instability of dicentric plasmids in yeast
Summary
Dicentric plasmids in yeast undergo rearrangements, primarily deleting centromere sequences. This instability is linked to interactions between centromeres and the cell
Area of Science:
- Yeast genetics
- Molecular biology
- Chromosome dynamics
Background:
- Dicentric plasmids, containing two centromeres, are inherently unstable in yeast.
- Previous research indicates the RAD52 gene product is crucial for DNA double-strand break repair.
Purpose of the Study:
- To investigate the stability and rearrangement mechanisms of dicentric plasmids in yeast.
- To determine the role of the RAD52 gene in the stability of dicentric plasmids.
Main Methods:
- In vitro construction of dicentric plasmids with varying centromere combinations (CEN4, CEN3).
- DNA transformation of yeast cells (RAD+ and rad52 mutant strains).
- Analysis of plasmid populations for rearrangements and deletions using colony heterogeneity.
Main Results:
- Dicentric plasmids consistently rearranged, involving deletion of one or both centromeres.
- RAD52 mutant yeast showed reduced transformation frequency and a lower ratio of unrearranged to deleted plasmids.
- Instability is proposed to result from mechanical breakage due to independent centromere interaction with the spindle apparatus.
Conclusions:
- Centromere-mediated instability drives dicentric plasmid rearrangements in yeast.
- The RAD52 gene influences the outcome of dicentric plasmid instability, suggesting a role in managing DNA breaks.
- A model involving mechanical breakage and subsequent deletion explains observed plasmid heterogeneity.
Related Concept Videos
01:28Yeast Signaling
Yeasts are single-celled organisms, but unlike bacteria, they are eukaryotes (cells with a nucleus). Cell signaling in yeast is similar to signaling in other eukaryotic cells. A ligand, such as a protein or a small molecule released from a yeast cell, attaches to a receptor on the cell surface. The binding stimulates second-messenger kinases to activate or inactivate transcription factors that further regulate gene expression. Many of the yeast intracellular signaling cascades have similar...
01:28Plasmids
Plasmids are extrachromosomal DNA molecules found in bacteria, archaea, and some eukaryotic microbes like yeast. These small, circular DNA structures typically contain fewer than 30 genes, although some may exist linearly. Plasmids vary in their number within a cell, known as copy number. Single-copy plasmids are present in one copy per cell and multi-copy plasmids are present in multiple copies, reaching over 100 copies per cell.Plasmids usually replicate independently of the chromosomal DNA...