Characterization Of Terminators In Streptomyces

Synthetic biology, as an emerging discipline of the century, holds a great promise for the pharmaceutical industry. Exploiting novel compounds have been the most effective way to resolve the crisis of multidrug resistance in bacteria due to antibiotics abuse. As we know, most of the natural products come from actinomycetey, especially Streptomyces. Therefore, the use of synthetic biology to obtain new compounds from Streptomyces has attracted much attention in recent research including a breakthrough on universal synthetic modular regulatory elements in Streptomyces. This thesis mainly focused on screening and characterizing new terminators in Streptomyces.Firstly, synthetic terminators have been screened and characterized in Streptomyces. This work is based on platform for characterizing promoters and RBSs in our laboratory. We used a double reporter system to characterize a series of terminators in the Streptomyces host, and then we quantified their strengths through qRT-PCR. As a result, we acquired a series of terminators with dynamic range from 4.4-fold-57.8-fold, and they function well in Streptomyces venezuelae.To our surprise, we found the terminators not only showed strong termination efficiency, but also had an effect on the cognate gene. In order to verify this universality in Streptomyces, we randomly chose 10 terminators to test in Streptomyces coelicolor. The qualitative results indicate that the terminators still work well in Streptomyces coelicolor. Meanwhile, we also chose the lycopene biosynthetic gene cluster of Streptomyces avermitilis as a reporter. Finally, we applied strong terminators to solve the transcriptional read-through of aveR and aveF genes in S. avermitilis.In conclusion, this research provides a set of new terminators to promote the synthetic biological study in Streptomyces. Our work will be beneficial to synthetic biology community and facilitate the natural product discovery process in Streptomyces.