Vectors for yeast and other fungi
Yeast episomal plasmids
Image source: Figure 7.1, Gene Cloning & DNA Analysis- An Introduction, T.A.Brown. fifth edition, blackwell publishing, 2010
YEps were first constructed by Beggs (1978) by recombining an E. coli cloning vector with the naturally occurring yeast 2 µm plasmid. [3] The word “episomal” indicates that a YEp can replicate as an independent plasmid, but also implies that integration into one of the yeast chromosomes can occur. Integration occurs because the gene carried on the vector as a selectable marker is very similar to the mutant version of the gene present in the yeast chromosomal DNA. [4]
This plasmid is 6.3 kb in size, has a copy number of 50–100 per haploid cell and has no known function. [3] YEps have the highest transformation frequency providing between 10,000 and 100,000 transformed cells per μg. [4]
Image source: http://www.discoverbiotech.com/image/image_gallery?uuid=4d30c336-e5b5-41e1-85d9-65ac537e9cbf&groupId=11406&t=1332308806750
Reference:
- Principles and Techniques of Biochemistry and Molecular Biology , Wilson Keith and Walker John, seventh edition, cambridge university press, 2010
- Gene Cloning & DNA Analysis- An Introduction, T.A.Brown. fifth edition, blackwell publishing, 2010
- http://genome.jgi.doe.gov/public/Sacce1/yeast_2.jpg
- http://www.discoverbiotech.com
