EngineeredStreptomyces avermitilisHost for Heterologous Expression of Biosynthetic Gene Cluster for Secondary Metabolites

Abstract

An industrial microorganism Streptomyces avermitilis, which is a producer of anthelmintic macrocyclic lactones, avermectins, has been constructed as a versatile model host for heterologous expression of genes encoding secondary metabolite biosynthesis. Twenty of the entire biosynthetic gene clusters for secondary metabolites were successively cloned and introduced into a versatile model host S. avermitilis SUKA17 or 22. Almost all S. avermitilis transformants carrying the entire gene cluster produced metabolites as a result of the expression of biosynthetic gene clusters introduced. A few transformants were unable to produce metabolites but their production was restored by the expression of biosynthetic genes using an alternative promoter or the expression of a regulatory gene in the gene cluster that controls the expression of biosynthetic genes in the cluster using an alternative promoter. Production of metabolites in some transformants of the versatile host was higher than that of the original producers and cryptic biosynthetic gene clusters in the original producer were also expressed in a versatile host.

Terpene synthases are widely distributed in bacteria

“…The resultant mutant host has been shown to be particularly suited for the production of a wide variety of natural products (27,38,45,46). This versatile engineered host system, which has been stripped of all of its native terpene synthase genes and is, thus, unable to produce endogenous terpenoid metabolites that might otherwise interfere with production and analysis of heterologously expressed terpenes and their derivatives, is ideally suited to the generation of exogenous terpenoid metabolites in quantities sufficient for their rigorous spectroscopic analysis.…”

“…This versatile engineered host system, which has been stripped of all of its native terpene synthase genes and is, thus, unable to produce endogenous terpenoid metabolites that might otherwise interfere with production and analysis of heterologously expressed terpenes and their derivatives, is ideally suited to the generation of exogenous terpenoid metabolites in quantities sufficient for their rigorous spectroscopic analysis. Using this method, individual genes encoding monoterpene, sesquiterpene, or diterpene synthases, including their native or heterologous ribosome-binding sequences, can be inserted downstream of the appropriate genes for GPP synthase (gps), FPP synthase (fps), or GGPP synthase (ggs) under the control of a strong, constitutively expressed promoter (rpsJp) harbored in the integrating vector pKU1021 (46). Coexpression of the gene for the relevant polyprenyl diphosphate synthase (Fig.…”

Antiviral Activity of Secondary Metabolites Produced by Streptomyces Species Isolated From Egyptian Soil.

“…Streptomyces Avermitilis was recorded as industrial microorganism that produce diverse secondary metabolites like macrocyclic lactones, milbemycin, and avermectins (Komatsu et al, 2013).…”

Characterization of bafilomycin biosynthesis in Kitasatospora setae KM-6054 and comparative analysis of gene clusters in Actinomycetales microorganisms

“…The resulting transformants carrying the gene cluster for bafilomycin biosynthesis produced bafilomycins A 1 and B 1 . 21 The BAC clone contained the 102.4 kb region of K. setae KM-6054 corresponding to 8 331 035-8 433 476 nt of the K. setae KM-6054 genome, which consisted of 48 ORFs (KSE_73350-KSE_73800) including genes involved in bafilomycin biosynthesis (bfm). The 102.4 kb region described above contained the entire gene cluster for bafilomycin biosynthesis, as transformants produced bafilomycins in the heterologous host.…”