Project description:The terminal compartments of Streptomyces are less prone to transcription than the rest of the chromosome. Indeed, the expression of the highly variable regions enriched in those compartments is generally conditional and often requires an empirical approach to characterize the inducing conditions. For instance, in the context of identifying adequate antibiotic production conditions, an OSMAC (“One Strain Many Compounds”) approach is frequently implemented, based on strain cultivation in different environmental conditions (composition of the medium, growth time, temperature, co-cultures, etc.). Likewise, to find the expression conditions of a complete prophage of Streptomyces ambofaciens ATCC 23877 (named 'Samy' phage/prophage), we conducted a similar approach by analyzing the transcriptomes in five solid media (HT, SAF, ONA, MMM, MMM+NAG). The terminal compartments of Streptomyces are less prone to transcription than the rest of the chromosome. Indeed, the expression of the highly variable regions enriched in those compartments is generally conditional and often requires an empirical approach to characterize the inducing conditions. For instance, in the context of identifying adequate antibiotic production conditions, an OSMAC (“One Strain Many Compounds”) approach is frequently implemented, based on strain cultivation in different environmental conditions (composition of the medium, growth time, temperature, co-cultures, etc.). Likewise, to find the expression conditions of a complete prophage of Streptomyces ambofaciens ATCC 23877 (named 'Samy' phage/prophage), we conducted a similar approach by analyzing the transcriptomes in five solid media (HT, SAF, ONA, MMM, MMM+NAG).
Project description:Background: During the lifetime of a fermenter culture, the soil bacterium S. coelicolor undergoes a major metabolic switch from exponential growth to antibiotic production. We have studied gene expression patterns during this switch, using a specifically designed Affymetrix genechip and a high-resolution time-series of fermenter-grown samples. Results: Surprisingly, we find that the metabolic switch actually consists of multiple finely orchestrated switching events. Strongly coherent clusters of genes show drastic changes in gene expression already many hours before the classically defined transition phase where the switch from primary to secondary metabolism was expected. The main switch in gene expression takes only 2 hours, and changes in antibiotic biosynthesis genes are delayed relative to the metabolic rearrangements. Furthermore, global variation in morphogenesis genes indicates an involvement of cell differentiation pathways in the decision phase leading up to the commitment to antibiotic biosynthesis. Conclusions: Our study provides the first detailed insights into the complex sequence of early regulatory events during and preceding the major metabolic switch in S. coelicolor, which will form the starting point for future attempts at engineering antibiotic production in a biotechnological setting. Keywords: time course
Project description:To help understand the functions of GBL receptor ScbR and antibiotic receptor ScbR2, the global transcriptional profiles of scbRDM and scbR2DM compared to WT were studied.