Shuttle Vectors,Prokaryotic Species,Streptomyces Plasmid,Antibiotic Resistance,Eukaryotic Vectors

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	Shuttle Vectors - These vectors have been designed to replicate in cells of two different species; therefore, they contain two origins of replication, one specific for each host species, as well as those genes necessary for their replication and not provided by the host cells. These vectors are created by recombinant techniques. Some of them can be grown in two different prokaryotic species, while others can propagate in a prokaryotic species, usually E. coli, and a eukaryotic one, e.g. yeast, plants, animals. Since these vectors can be grown in one host and then moved into another without any extra manipulation, they are called shuttle vectors.
A shuttle vector designed to replicate in E. coli and Streptomyces has been constructed as follows: (1) the modules for DNA replication in Streptomyces and methylenomycin A resistance are derived from a streptomyces plasmid, and (2) the replication module for maintenance in E. coli and a gene for antibiotic resistance are taken from an E. coli plasmid. This shuttle vector allows the initial cloning of Streptomyces DNA inserts in E. coli and their subsequent functional tests in Streptomyces. Shuttle vectors have been designed to specifically satisfy this need, i.e., the initial cloning of DNA inserts in E. coli and subsequent functional tests in the species to which the DNA inserts belong. Most of the eukaryotic vectors are, in fact, shuttle vectors.