Cloning and expression vectors for a Gram-positive host, Streptomyces lividans.

ABSTRACT

The choice of an expression system for the meta-genomic DNA of interest is of vital importance for the detection of any particular gene or gene cluster. Most of the screens to date have used the Gram-negative bacterium Escherichia coli as a host for the meta-genomic gene libraries. However, the use of E. coli introduces a potential host bias since only 40% of the enzymatic activities may be readily recovered by random cloning in E. coli (Gabor et al., Environ Microbiol 6879-886, 2004). To recover some of the remaining 60%, alternative cloning hosts such as Streptomyces spp. have been used (Lorenz and Eck, Nat Rev Microbiol 3510-516, 2005). Streptomycetes are high-GC Gram-positive bacteria that belong to the Actinomycetales, and they have been studied extensively in the last 10 years as an alternative expression system (reviewed in Vrancken and Anné, Future Microbiol 4181-188, 2009). Streptomyces is extremely well suited for the expression of DNA from other actinomycetes and genomes of high GC content (Wang et al., Org Lett 22401-2404, 2000). Furthermore, due to its high innate secretion capacity, it can be a superior system than E. coli for the production of many extra-cellular proteins.