Investigation of Cell Division Genes in Streptomyces coelicolor

Tan, Xiao (2018) Investigation of Cell Division Genes in Streptomyces coelicolor. Doctoral thesis, University of East Anglia.

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Streptomyces coelicolor is a Gram-positive, filamentous, high G-C content bacterium with a complex developmental life cycle involving differentiation into distinct tissues, such as the vegetative hyphae, aerial hyphae and spores. Unlike in other bacteria, cell division in Streptomyces. coelicolor is only required for sporulation rather than for viability. The key protein FtsZ, which assembles into Z-rings, marks the positions for future, regularly spaced septation that transforms the aerial hyphae into spores, is essential for septation during sporulation in S. coelicolor. The function of several genes, located between ftsZ (SCO2082) and divIVA (SCO2077) in the chromosome, have not been well characterised, despite the fact they are downstream of ftsZ in many Gram-positive bacteria, including Streptomyces. In this study we mainly focus on three genes SCO2081, SCO2080, SCO2079 (sepF), located downstream of ftsZ. SepF was previously shown to tether the Z-ring to the membrane in Bacillus. subtilis and promote FtsZ protofilament formation. Considering the chromosomal location, important roles in cell division or cell-wall synthesis were anticipated.
In this work, we generated knockout mutant strains by the deletion of these three genes and confirmed the mutant strains generated. We characterized the mutant phenotypes using macroscopic observations and extensive microscopic analysis focusing on possible effects on the division process and cell-wall synthesis. We also monitored the localisation of the SepF protein during development of S. coelicolor in order to explore its role during the Z-ring assembly and positioning. The severe defect of septum formation in the the sepF (SCO2079) knockout mutant suggested a key role for SepF in the early stages of cell division in Streptomyces, which is different to the role of the B. subtilis SepF in the late stages of septum formation. The gene knockouts of the surrounding genes SCO2080 and SCO2081 resulted in less severe, more subtle phenotype, nevertheless affecting the efficiency of septation and cell division in Streptomyces.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Megan Ruddock
Date Deposited: 19 Feb 2019 14:39
Last Modified: 26 Mar 2021 01:39

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