Micromonospora RNA polymerase activity changes during stationary phase

RNA polymerase was isolated from Micromonospora echinospora and from Streptomyces lividans. In vitro transcription of a DNA fragment containing multiple tandem promoters from Micromonospora followed the pattern of expression observed previously for in vivo studies. RNA polymerase was prepared from cultures of Micromonospora that were harvested during the growing phase and during the stationary phase. Promoters that were utilized in Micromonospora only during the stationary phase were utilized in vitro only when RNA polymerase was purified from a stationary-phase culture, and not when RNA polymerase was purified from growing cells.