Optimization of gene expression inStreptomyces tividansby a transcription terminator

Abstract
The ability of an inverted repeat sequence (IRS) from the 3' end of the aph gene from Streptomvces fradiae to induce transcription termination in vivo has been examined. As a model system, a DNA fragment encoding the human interferon ∝ 2 inserted in the Streptomyces plasmid pIJ702 was used. When the IRS was inserted downstream from this sequence and transcription assayed in Streptomyces lividans, highly efficient (∼90%) transcription termination was observed occurring immediately after the 3' terminus of the dyad. In contrast, gene constructions lacking the IRS transcribed longer mRNAs. Moreover, the IRS gave rise to increased amounts of the hlFN ∝ 2 suggesting that the putative stem-loop structure stabilised the transcript.