Study of cell division genes sepF, SCO2078 and divIVA in Streptomyces coelicolor

Kaur, Sundeep (2018) Study of cell division genes sepF, SCO2078 and divIVA in Streptomyces coelicolor. Doctoral thesis, University of East Anglia.

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Streptomyces coelicolor is a model organism for growth and cell division, with a unique advantage for using this organism for studying cell division since this bacterium does not require division for its viability, but only for sporulation. S. coelicolor contains a gene cluster of six genes that are key for growth and division. Only two members of this gene cluster, ftsZ and divIVA has been well characterized, while the role of the other four genes are not yet fully established. FtsZ is a ubiquitous protein for cell division in bacteria, a key for initiating division. FtsZ marks the position of septum formation and recruits a number of proteins to this position forming the so called divisome complex, to complete division. On the other hand, DivIVA has been shown to be essential for growth, which in Streptomyces takes place exclusively at hyphal tips. The genetic location of the remaining genes suggests that they may be important for either polar growth or division.

This study investigated different aspects of the biological role of three genes of this cluster, namely sepF, SCO2078 and divIVA genes, which encompass one half of the cell growth and division cluster. The phenotypes of the knockout mutants of sepF and SCO2078 were characterised by monitoring cellular development macroscopically on solid medium. In addition, epi-fluorescence microscopy was used to analyse both cell wall and chromosomal DNA in these mutants compared to the wild-type strain. Also, the effect of overproduction of both SepF and SCO2078 proteins in S. coelicolor was tested using the vector pIJ6902, one of the few variable inducible overexpression vectors available for Streptomyces research. This study identified some of the shortcomings of the pIJ6902 vector, including the accessibility of the inducer to the different cellular compartments within the complex Streptomyces colony and the importance of efficient translation of the genes cloned into pIJ6902. It was also shown that the sequences upstream of the translational start points had a major effect on the efficiency of overexpression of proteins. Additionally, polar growth and DivIVA localisation under selected stress conditions was investigated.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Users 9280 not found.
Date Deposited: 12 Jun 2019 11:32
Last Modified: 01 Oct 2021 01:55


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