Gene Technological Studies of an alpha-Amylase Based Expression System in'Streptomyces'. 2. Cloning and Regulation of an alpha-Amylase Gene in 'Streptomyces lividans'. (Gentekniska Studier av ett alpha-Amylasbaserat Proteinproduktionssystem i 'Streptomyce

摘要

Streptomyces is a Gram-positive soil bacteria which during the last 50 years hasreceived much interest due to its ability to produce secondary metabolites such as antibiotics and industrial enzymes. Streptomyces are well suited as host for production of foreign proteins and hence expression system in the bacteria are under development. The authors constructed a regulated expression vector for production and secretion of heterologous proteins. The vector is based on the starch-inducible promoter and the signals for secretion from an alpha-amylase gene from a compostisolate of Streptomyces. Expression levels of the heterologous genes in the secretion vector were lower than the alpha-amylase gene expression levels in the original strain (Osterman et al., 1992). Therefore, a study on the regulatory region of the alpha-amylase was performed. Here they described the cloning and characterization of the alpha-amylase gene and its control regions. It is shown that an upstream activating element is of importance for the gene activity. Quantitative RNA analysis indicate that besides the transcriptional control exerted by the upstream activating element there are post-transciptional mechanisms contributing to the control of gene expression.