Type II Toxin–Antitoxin Systems in the Unicellular Cyanobacterium Synechocystis sp. PCC 6803
Faculty of Biology, Institute of Biology 3, Genetics and Experimental Bioinformatics, University of Freiburg, Schänzlestr. 1, D-79104 Freiburg, Germany
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Academic Editor: Anton Meinhart
Toxins 2016, 8(7), 228; https://doi.org/10.3390/toxins8070228
Received: 20 June 2016
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Accepted: 11 July 2016
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Published: 21 July 2016
(This article belongs to the Special Issue Toxin-Antitoxin System in Bacteria)
Bacterial toxin–antitoxin (TA) systems are genetic elements, which are encoded by plasmid as well as chromosomal loci. They mediate plasmid and genomic island maintenance through post-segregational killing mechanisms but may also have milder effects, acting as mobile stress response systems that help certain cells of a population in persisting adverse growth conditions. Very few cyanobacterial TA system have been characterized thus far. In this work, we focus on the cyanobacterium Synechocystis 6803, a widely used model organism. We expand the number of putative Type II TA systems from 36 to 69 plus seven stand-alone components. Forty-seven TA pairs are located on the chromosome and 22 are plasmid-located. Different types of toxins are associated with various antitoxins in a mix and match principle. According to protein domains and experimental data, 81% of all toxins in Synechocystis 6803 likely exhibit RNase activity, suggesting extensive potential for toxicity-related RNA degradation and toxin-mediated transcriptome remodeling. Of particular interest is the Ssr8013–Slr8014 system encoded on plasmid pSYSG, which is part of a larger defense island or the pSYSX system Slr6056–Slr6057, which is linked to a bacterial ubiquitin-like system. Consequently, Synechocystis 6803 is one of the most prolific sources of new information about these genetic elements.
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Keywords:
bacterial toxins; cyanobacteria; hydrogenase; PIN-domain; cibonuclease; RNA degradation; RNA interferase; RNA turnover; toxin–antitoxin; VapC
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MDPI and ACS Style
Kopfmann, S.; Roesch, S.K.; Hess, W.R. Type II Toxin–Antitoxin Systems in the Unicellular Cyanobacterium Synechocystis sp. PCC 6803. Toxins 2016, 8, 228. https://doi.org/10.3390/toxins8070228
AMA Style
Kopfmann S, Roesch SK, Hess WR. Type II Toxin–Antitoxin Systems in the Unicellular Cyanobacterium Synechocystis sp. PCC 6803. Toxins. 2016; 8(7):228. https://doi.org/10.3390/toxins8070228
Chicago/Turabian StyleKopfmann, Stefan, Stefanie K. Roesch, and Wolfgang R. Hess. 2016. "Type II Toxin–Antitoxin Systems in the Unicellular Cyanobacterium Synechocystis sp. PCC 6803" Toxins 8, no. 7: 228. https://doi.org/10.3390/toxins8070228
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