ParH: a novel regulator of septum site placement in Streptomyces coelicolor

Gillespie, Michael (2017) ParH: a novel regulator of septum site placement in Streptomyces coelicolor. Doctoral thesis, University of East Anglia.

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Streptomyces coelicolor is a Gram-positive, GC-rich, soil-dwelling, filamentous bacterium with a complex life cycle, which begins from a single uni-genomic spore. The life cycle is completed after the differentiation of multi-genomic aerial hyphae into uni-genomic spores. This process requires the segregation and organisation of many chromosomes of the sporogenic hyphae which are then compartmentalised by the synchronous placement of 20-50 septa, generating a single chromosome in each pre-spore compartment. Chromosome segregation and septum site-placement are two key components of cell division. Throughout the bacterial kingdom, these processes are controlled by the ParA/MinD superfamily of proteins. These proteins can be divided into two categories according to their function: those involved in chromosome segregation and those involved in septum-site placement.
In S. coelicolor, the only characterised protein belonging to this superfamily is ParA that has been implicated in chromosome segregation along with its partner protein, ParB. Prior to septation, ParA forms long filaments along the length of the hyphae where they position ParB bound to the chromosomes. This study characterises a novel homologue of the ParA/MinD superfamily encoded by the gene SCO1772, which we have designated parH. We also characterised the gene (SCO1771), which is downstream of parH and translationally coupled. Through in vitro techniques such as analytical gel filtration, native-PAGE, chemical crosslinking, pelleting assays we have characterised their oligomerisation, determined their protein:protein interactions and present structural data for SCO1771. We show that ParH is involved in the determination of septum site placement during division. We also link ParH to both the chromosome segregation machinery and the tip organising centre (TIPOC), a multi protein assembly that drives growth. This work helps to clarify the link between chromosome segregation and septum site placement.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Jackie Webb
Date Deposited: 09 May 2018 11:25
Last Modified: 31 Mar 2020 00:38


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