Project Details
Projekt
Functional dissection of the Bacillus subtilis SPbeta prophage lysogeny-lysis decision system and characterization of a novel SPbeta defense system
Applicant
Professor Dr. Fabian M. Commichau
Subject Area
Metabolism, Biochemistry and Genetics of Microorganisms
Term
since 2024
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 548311592
The temperate phage SPbeta infects the endospore-forming Gram-positive bacterium Bacillus subtilis and resides as a prophage in its genome. Cultures of B. subtilis that are lysogenic for SPbeta release the glycopeptide sublancin, which inhibits the growth of SPbeta-free B. subtilis strains by interfering with DNA replication and transcription. Thus, SPbeta is a host-benefitting trait after the transfer to another B. subtilis strain lacking the prophage previously. Phages of the SPbeta group like phi3T use a peptide-based communication system (termed the “arbitrium” system) to coordinate lysis-lysogeny decisions. In the early stage of infection, the number of phages and the peptide concentration is low and a transcription antiterminator protein allows the synthesis of an antitoxin. Consequently, lytic transcripts are not degraded and SPbeta remains in the lytic cycle. With increasing peptide concentrations, the peptide enters the cell and inactivates the transcription antiterminator protein. The lytic transcripts are degraded, and the phages enters the lysogenic state. Recently, we have identified the master repressor of SPbeta and a factor that acts downstream of the repressor and is critical for the activation of the lytic cycle. Although many additional components of the lysis-lysogeny decision system have already been identified, it is unclear how the lysogenic cycle, particularly in the case of the phage SPbeta, is activated. By pursuing genetic, biochemical, and structural studies, we aim to elucidate the molecular details of the lysis-lysogeny decision system of the temperate phage SPbeta. We also wish to study the putative SPbeta defense system that is encoded on an Escherichia coli-B. subtilis shuttle vector.
DFG Programme
Priority Programmes
