Vectors for yeast and other fungi

Yeast replicative plasmids (YRps) 

Image source : Figure 7.3, Gene Cloning & DNA Analysis- An Introduction, T.A.Brown. fifth edition, blackwell publishing, 2010 

YRps were initially constructed by Struhl et al. (1979). 

They isolated chromosomal fragments of DNA which carry sequences that enable E. coli vectors to replicate in yeast cells. [3]  

YRps are able to multiply as independent plasmids because they carry a chromosomal DNA sequence that includes an origin of replication. Replication origins are known to be located very close to several yeast genes, including one or two which can be used as selectable markers. [4] 

YRps are also quite productive, giving between 1000 and 10,000 transformants per μg and a copy number of 5-100. [4]

YRp7 is an example of a replicative plasmid. It is made up of pBR322 plus the yeast gene TRP1. This gene, which is involved in tryptophan biosynthesis, is located adjacent to a chromosomal origin of replication. The yeast DNA fragment present in YRp7 contains both TRP1 and the origin. [4]  

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 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