Construction of pDYN6902, a new Streptomyces integrative expression vector designed for cloning sequences interfering with Escherichia coli viability

• We built pDYN6902, an E. coli/Streptomyces shuttle vector derived from pIJ6902.
• pDYN6902 is a low copy number plasmid in E. coli.
• Unlike pIJ6902, pDYN6902 enables the cloning of deleterious genes in E. coli.
• Its reduced copy number limits deleterious effects of the tipA promoter leak.

We describe here the construction of a new version of the Escherichia coli–Streptomyces shuttle cloning vector pIJ6902, which carries the original thiostrepton-inducible PtipA as well as the integrative and cloning systems, but with the E. coli low copy number replication control of the F (fertility) factor. The rationale of this construct was to provide a shuttle cloning vector to enable the cloning of genes whose expression is toxic in E. coli while keeping the efficient regulated expression system for Streptomyces as its ascendant vector pIJ6902. This new vector named pDYN6902 (10,975 bp) showed a copy-number reduced 12 times compared to that of pIJ6902 and indeed a decreased expression of the cloned gene. It was also shown to allow the successful cloning in E. coli of a deleterious gene, i.e. I-SceI meganuclease encoding gene.