What is yeast 2 micron plasmid?

The 2 µm plasmid is a benign parasitic plasmid harbored in the nucleus of most strains of the budding yeast, Saccharomyces cerevisiae (For review see [1] and [2]). Despite providing no selective advantage to the host, the plasmid is faithfully maintained at ∼60 copies per cell [3].

Does Saccharomyces cerevisiae have circular DNA?

cerevisiae genome, suggesting that a substantial fraction of the yeast genome is prone to circularization (Fig. S4).

What are 2μm plasmids?

The 2μm circle, a relatively small circular plasmid (6,318 bp) present in most common strains of Saccharomyces cerevisiae, has optimized a partitioning system and an amplification system that allow it to be propagated stably in a cell population at a copy number of approximately 60 to 100 per cell (reviewed in …

What is yeast recombination?

Yeast recombination: the association between double-strand gap repair and crossing-over.

What is 2 micron Ori?

2 micron DNA is the only known example of a multiple-copy, extrachromosomal DNA in which every molecule replicates in each cell cycle. Quantitative analysis of the data indicates that 2 micron DNA replication is limited to a fraction of the cell cycle.

What is circular DNA called?

A plasmid is a small circular DNA molecule found in bacteria and some other microscopic organisms. Plasmids are physically separate from chromosomal DNA and replicate independently.

What is the function of circular DNA?

Functional DNA vectors are circular molecules of DNA calledplasmids that contain various additional genetic elements that modulate gene expression, termedpromoters and enhancers, that are required to achieve expression of the gene product at therapeutic levels (Fig.

What is homologous recombination yeast?

Homologous recombination is an important pathway for error-free repair of DNA lesions, such as single-and double-strand breaks, and for rescue of collapsed replication forks.

What is Saccharomyces cerevisiae 2 micron plasmid?

The 2 micron plasmid of Saccharomyces cerevisiae is a relatively small multi-copy selfish DNA element that resides in the yeast nucleus at a copy number of 40-60 per haploid cell. The plasmid is able to persist in host populations with almost chromosome-like stability with the help of a partitioning system and a copy number control system.

What is a 2 micron circle plasmid?

The 2 micron circle is a small double stranded DNA plasmid that occurs at about 60 copies per cell in the nuclei of virtually all strains of Saccharomyces cerevisiae. The plasmid has no apparent phenotypic effect on host cells, and is the basis of many useful vectors for the transformation of yeast.

What can a 2 micron plasmid teach us about chromosome stability?

Summary and perspectives The 2 micron plasmid provides a model for how the collaboration between an efficient partitioning system and a copy number control system can confer chromosome-like stability on an extremely simple extra-chromosomal genome.

What is the size of a 2 micron circle?

The 2 micron circle, which exists in the nucleus at an average copy number of 40–60, is approximately 6.3 kbp long, with a coding capacity for only four proteins ( Fig. 1 ). The plasmid is remarkably stable in host populations, the loss rate of 10 −4 –10 −5 per cell division being only about 10-fold higher than that of chromosomes.