Maintenance of the virulence plasmid in Shigella flexneri is influenced by Lon and two functional partitioning systems

McVicker, G ORCID: https://orcid.org/0000-0002-6967-5968, Hollingshead, S, Pilla, G and Tang, CM, 2019. Maintenance of the virulence plasmid in Shigella flexneri is influenced by Lon and two functional partitioning systems. Molecular Microbiology. ISSN 0950-382X

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Abstract

Members of the genus Shigella carry a large plasmid, pINV, which is essential for virulence. In Shigella flexneri, pINV harbours three toxin -antitoxin (TA) systems, CcdAB, GmvAT and VapBC that promote vertical transmission of the plasmid. Type II TA systems, such as those on pINV, consist of a toxic protein and protein antitoxin. Selective degradation of the antitoxin by proteases leads to the unopposed action of the toxin once genes encoding a TA system have been lost, such as following failure to inherit a plasmid harbouring a TA system. Here, we investigate the role of proteases in the function of the pINV TA systems and demonstrate that Lon, but not ClpP, is required for their activity during plasmid stability. This provides the first evidence that acetyltransferase family toxin -antitoxin systems, such as GmvAT, can be regulated by Lon. Interestingly, Shigella flexneri pINV also harbours two putative partitioning systems, ParAB and StbAB. We show that both systems are functional for plasmid maintenance although their activity is masked by other systems on pINV . Using a model vector based on the pINV replicon, we observe temperature -dependent differences between the two partitioning systems that contribute to our understanding of the maintenance of virulence in Shigella species.

Item Type:	Journal article
Publication Title:	Molecular Microbiology
Creators:	McVicker, G., Hollingshead, S., Pilla, G. and Tang, C.M.
Publisher:	John Wiley & Sons Ltd.
Date:	14 February 2019
ISSN:	0950-382X
Identifiers:	Number Type 10.1111/mmi.14225 DOI
Divisions:	Schools > School of Science and Technology
Record created by:	Jill Tomkinson
Date Added:	05 Mar 2019 14:19
Last Modified:	28 Mar 2019 10:47
URI:	https://irep.ntu.ac.uk/id/eprint/35894

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