Please use this identifier to cite or link to this item:
http://hdl.handle.net/11375/27733
Title: | Regulation of Specialized Metabolism in Streptomyces |
Authors: | Zhang, Xiafei |
Advisor: | Elliot, Marie |
Department: | Biology |
Keywords: | Streptomyces;Specialized metabolism;Nucleoid-associated protein;Regulation |
Publication Date: | 2022 |
Abstract: | In Streptomyces bacteria, the expression of many antibiotic biosynthetic clusters is controlled by both cluster-specific regulators and more globally-acting regulators; however, much remains unknown about the factors that govern antibiotic production. In Streptomyces venezuelae, we have discovered that the broadly-conserved nucleoid-associated protein Lsr2, plays a major role in repressing specialized metabolic cluster gene expression. To understand how Lsr2 exerts its gene silencing effects, we focused our attention on the well-studied, but transcriptionally silent, chloramphenicol cluster in S. venezuelae. We established that Lsr2 represses transcription of the chloramphenicol cluster by binding DNA both within the cluster and at distal positions. CmlR is a known activator of the chloramphenicol cluster, but expression of its associated gene is not under Lsr2 control. We discovered that CmlR functions to ‘counter-silence’ Lsr2 activity, alleviating Lsr2 repression and permitting chloramphenicol production, by recruiting RNA polymerase. Lsr2 plays a central role in controlling antibiotic production in Streptomyces; however, beyond this counter-silencing activity, little is known about how Lsr2 is regulated. We identified regulators that could control the expression of lsr2, and found that Lsr2 and LsrL, an Lsr2 homologue that is encoded by all streptomycetes, interact directly with each other, and that their respective DNA-binding activities are altered by the presence of the other protein. These data suggest that LsrL may impact Lsr2 activity in regulating antibiotic production in Streptomyces. Beyond Lsr2, we wanted to develop a comprehensive understanding of the regulatory proteins that impact biosynthetic gene cluster expression. To define the regulatory protein occupancy of antibiotic clusters, we developed ‘in vivo protein occupancy display-high resolution’ (IPOD-HR) technology for use in Streptomyces. This work will lay the foundation for establishing a comprehensive regulatory network map for biosynthetic clusters in Streptomyces, and guide future work aimed at stimulating the expression of metabolic clusters in any Streptomyces species. |
URI: | http://hdl.handle.net/11375/27733 |
Appears in Collections: | Open Access Dissertations and Theses |
Files in This Item:
File | Description | Size | Format | |
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Zhang_Xiafei_202207_PhD.pdf | 9.33 MB | Adobe PDF | View/Open |
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