Construction of Streptomyces specific recombinant vectors containing the streptomycin regulatory gene isolated from an Iranian Streptomyces griseus

The streptomycin regulatory gene, strR, from Streptomyces griseus, is a pathway specific regulator of streptomycin biosynthesis gene cluster. Here, two different sets of primers were designed (Oligo5) in order to amplify the strR. The gene was initially isolated from the Iranian strain of S. griseus (PTCC1127) and also the American strain ATCC1952. It was then confirmed as strR by semi-Nested PCR and RFLP PCR. The amplified gene (1134 bp) has two defined recognition sites for BamHI and XbaI. Therefore, it was cloned in E. coli, using a Streptomyces integrative specific vector pMA::hyg. The recombinant plasmid pSPstrR was then constructed and cloned in E. coli. The isolated strR gene was also cloned in E. coli, using the multi-copy and expression vector pBluescript in order to overproduce the StrR protein. The structures of these new constructs were also confirmed. The structural analyses of the new constructs were performed by gel electrophoresis and PCR. These vectors could be used for site directed mutagenesis, gene replacement and deletion strategies in Streptomyces griseus. Overproduced StrR protein could be used directly for early onset induction and overproduction of antibiotic.