The ZorO-OrzO type I toxin–antitoxin locus: repression by the OrzO antitoxin

Type I toxin–antitoxin loci consist of two genes: a small, hydrophobic, potentially toxic protein, and a small RNA (sRNA) antitoxin. The sRNA represses toxin gene expression by base pairing to the toxin mRNA. A previous bioinformatics search predicted a duplicated type I locus within Escherichia col...

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Autores principales: Wen, Jia, Won, Daniel, Fozo, Elizabeth M.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2014
Materias:
RNA
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3919570/
https://www.ncbi.nlm.nih.gov/pubmed/24203704
http://dx.doi.org/10.1093/nar/gkt1018
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author Wen, Jia
Won, Daniel
Fozo, Elizabeth M.
author_facet Wen, Jia
Won, Daniel
Fozo, Elizabeth M.
author_sort Wen, Jia
collection PubMed
description Type I toxin–antitoxin loci consist of two genes: a small, hydrophobic, potentially toxic protein, and a small RNA (sRNA) antitoxin. The sRNA represses toxin gene expression by base pairing to the toxin mRNA. A previous bioinformatics search predicted a duplicated type I locus within Escherichia coli O157:H7 (EHEC), which we have named the gene pairs zorO-orzO and zorP-orzP. We show that overproduction of the zorO gene is toxic to E. coli; co-expression of the sRNA OrzO can neutralize this toxicity, confirming that the zorO-orzO pair is a true type I toxin–antitoxin locus. However, OrzO is unable to repress zorO in a strain deleted for RNase III, indicating that repression requires cleavage of the target mRNA. Sequence analysis and mutagenesis studies have elucidated a nucleotide sequence region (V1) that allows differential recognition of the zorO mRNA by OrzO and not OrzP, and a specific single nucleotide within the V1 of OrzO that is critical for repression of zorO. Although there are 18 nt of complementarity between the OrzO sRNA and the zorO mRNA, not all base pairing interactions are needed for repression; however, the amount needed is dependent on whether there is continuous or discontinuous complementarity to the target mRNA.
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spelling pubmed-39195702014-02-10 The ZorO-OrzO type I toxin–antitoxin locus: repression by the OrzO antitoxin Wen, Jia Won, Daniel Fozo, Elizabeth M. Nucleic Acids Res RNA Type I toxin–antitoxin loci consist of two genes: a small, hydrophobic, potentially toxic protein, and a small RNA (sRNA) antitoxin. The sRNA represses toxin gene expression by base pairing to the toxin mRNA. A previous bioinformatics search predicted a duplicated type I locus within Escherichia coli O157:H7 (EHEC), which we have named the gene pairs zorO-orzO and zorP-orzP. We show that overproduction of the zorO gene is toxic to E. coli; co-expression of the sRNA OrzO can neutralize this toxicity, confirming that the zorO-orzO pair is a true type I toxin–antitoxin locus. However, OrzO is unable to repress zorO in a strain deleted for RNase III, indicating that repression requires cleavage of the target mRNA. Sequence analysis and mutagenesis studies have elucidated a nucleotide sequence region (V1) that allows differential recognition of the zorO mRNA by OrzO and not OrzP, and a specific single nucleotide within the V1 of OrzO that is critical for repression of zorO. Although there are 18 nt of complementarity between the OrzO sRNA and the zorO mRNA, not all base pairing interactions are needed for repression; however, the amount needed is dependent on whether there is continuous or discontinuous complementarity to the target mRNA. Oxford University Press 2014-02 2013-11-06 /pmc/articles/PMC3919570/ /pubmed/24203704 http://dx.doi.org/10.1093/nar/gkt1018 Text en © The Author(s) 2013. Published by Oxford University Press. http://creativecommons.org/licenses/by/3.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle RNA
Wen, Jia
Won, Daniel
Fozo, Elizabeth M.
The ZorO-OrzO type I toxin–antitoxin locus: repression by the OrzO antitoxin
title The ZorO-OrzO type I toxin–antitoxin locus: repression by the OrzO antitoxin
title_full The ZorO-OrzO type I toxin–antitoxin locus: repression by the OrzO antitoxin
title_fullStr The ZorO-OrzO type I toxin–antitoxin locus: repression by the OrzO antitoxin
title_full_unstemmed The ZorO-OrzO type I toxin–antitoxin locus: repression by the OrzO antitoxin
title_short The ZorO-OrzO type I toxin–antitoxin locus: repression by the OrzO antitoxin
title_sort zoro-orzo type i toxin–antitoxin locus: repression by the orzo antitoxin
topic RNA
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3919570/
https://www.ncbi.nlm.nih.gov/pubmed/24203704
http://dx.doi.org/10.1093/nar/gkt1018
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