Show simple item record

dc.contributor.advisorFineran, Peter
dc.contributor.advisorRonson, Clive
dc.contributor.advisorSalmond, George
dc.contributor.authorDy, Ron Leonard
dc.identifier.citationDy, R. L. (2013). Investigation of the functional link between abortive infection and toxin-antitoxin systems (Thesis, Doctor of Philosophy). University of Otago. Retrieved from
dc.description.abstractBacteria are constantly faced by phage predation and various environmental stresses. In response, bacteria have amassed diverse genetic systems enabling their survival in ecological niches. Abortive infection (Abi) systems are ‘altruistic’ cell death modules activated in a phage-infected bacterium and provide protection to the clonal bacterial population. Previously, our analysis of ToxIN from Pectobacterium atrosepticum provided the first direct link between Abi and toxin-antitoxin (TA) systems and revealed a new type (type III) of TA mechanism. Here, we tested the functional overlaps between TA and Abi systems. We discovered that Lactococcus lactis AbiE system and a homologue situated in a genomic island in Streptococcus agalactiae function as TA systems. These TA systems have non-interacting protein components (i.e. are type IV TA systems) and are found in archaeal and bacterial genomes, plasmids and mobile genetic elements. The antitoxin has a winged-helix-turn-helix domain that binds a conserved inverted repeat and represses the transcription of the TA/Abi operon. Furthermore, the toxin functions through a mechanism not previously identified in TA systems. AbiEii is a nucleotidyltransferase that belongs to the DNA polymerase beta protein superfamily and specifically binds to GTP; however its molecular target remains to be classified. The identification of another Abi as a TA system further strengthens the model that a functional link exists between some Abi and TA systems.
dc.publisherUniversity of Otago
dc.rightsAll items in OUR Archive are provided for private study and research purposes and are protected by copyright with all rights reserved unless otherwise indicated.
dc.subjectAbortive infection
dc.titleInvestigation of the functional link between abortive infection and toxin-antitoxin systems
dc.language.rfc3066en of Microbiology and Immunology of Philosophy of Otago
otago.openaccessAbstract Only
 Find in your library

Files in this item


There are no files associated with this item.

This item is not available in full-text via OUR Archive.

If you are the author of this item, please contact us if you wish to discuss making the full text publicly available.

This item appears in the following Collection(s)

Show simple item record