Mutations at the URA3 locus of Saccharomyces cerevisiae can be obtained by a positive selection. Wild-type strains of yeast (or ura3 mutant strains containing a plasmid-borne URA3+ gene) are unable to grow on medium containing the pyrimidine analog 5-fluoro-orotic acid, whereas ura3- mutants grow no
A counterselection for the tryptophan pathway in yeast: 5-fluoroanthranilic acid resistance
โ Scribed by Toyn, Jeremy H.; Gunyuzlu, Paul L.; Hunter White, W.; Thompson, Lorin A.; Hollis, Gregory F.
- Book ID
- 101224517
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 178 KB
- Volume
- 16
- Category
- Article
- ISSN
- 0749-503X
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โฆ Synopsis
The ability to counterselect, as well as to select for, a genetic marker has numerous applications in microbial genetics. Described here is the use of 5-fluoroanthranilic acid for the counterselection of TRP1, a commonly used genetic marker in the yeast Saccharomyces cerevisiae. Counterselection using 5-fluoroanthranilic acid involves antimetabolism by the enzymes of the tryptophan biosynthetic pathway, such that trp1, trp3, trp4 or trp5 strains, which lack enzymes required for the conversion of anthranilic acid to tryptophan, are resistant to 5-fluoroanthranilic acid. Commonly used genetic procedures, such as selection for loss of a chromosomally integrated plasmid, and a replica-plating method to rapidly assess genetic linkage in self-replicating shuttle vectors, can now be carried out using the TRP1 marker gene. In addition, novel tryptophan auxotrophs can be selected using 5-fluoroanthranilic acid.
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