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Efficiency of integron cassette insertion in correct orientation is ensured by the interplay of the three unpaired features of attC recombination sites
The integron is a bacterial recombination system that allows acquisition, stockpiling and expression of cassettes carrying protein-coding sequences, and is responsible for the emergence and rise of multiresistance in Gram-negative bacteria. The functionality of this system depends on the insertion o...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Oxford University Press
2016
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5027507/ https://www.ncbi.nlm.nih.gov/pubmed/27496283 http://dx.doi.org/10.1093/nar/gkw646 |
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author | Nivina, Aleksandra Escudero, José Antonio Vit, Claire Mazel, Didier Loot, Céline |
author_facet | Nivina, Aleksandra Escudero, José Antonio Vit, Claire Mazel, Didier Loot, Céline |
author_sort | Nivina, Aleksandra |
collection | PubMed |
description | The integron is a bacterial recombination system that allows acquisition, stockpiling and expression of cassettes carrying protein-coding sequences, and is responsible for the emergence and rise of multiresistance in Gram-negative bacteria. The functionality of this system depends on the insertion of promoterless cassettes in correct orientation, allowing their expression from the promoter located upstream of the cassette array. Correct orientation is ensured by strand selectivity of integron integrases for the bottom strand of cassette recombination sites (attC), recombined in form of folded single-stranded hairpins. Here, we investigated the basis of such strand selectivity by comparing recombination of wild-type and mutated attC sites with different lengths, sequences and structures. We show that all three unpaired structural features that distinguish the bottom and top strands contribute to strand selectivity. The localization of Extra-Helical Bases (EHBs) directly favors integrase binding to the bottom strand. The Unpaired Central Spacer (UCS) and the Variable Terminal Structure (VTS) influence strand selectivity indirectly, probably through the stabilization of the bottom strand and the resulting synapse due to the nucleotide skew between the two strands. These results underscore the importance of the single-stranded nature of the attC site that allows such tight control over integron cassette orientation. |
format | Online Article Text |
id | pubmed-5027507 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | Oxford University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-50275072016-09-21 Efficiency of integron cassette insertion in correct orientation is ensured by the interplay of the three unpaired features of attC recombination sites Nivina, Aleksandra Escudero, José Antonio Vit, Claire Mazel, Didier Loot, Céline Nucleic Acids Res Molecular Biology The integron is a bacterial recombination system that allows acquisition, stockpiling and expression of cassettes carrying protein-coding sequences, and is responsible for the emergence and rise of multiresistance in Gram-negative bacteria. The functionality of this system depends on the insertion of promoterless cassettes in correct orientation, allowing their expression from the promoter located upstream of the cassette array. Correct orientation is ensured by strand selectivity of integron integrases for the bottom strand of cassette recombination sites (attC), recombined in form of folded single-stranded hairpins. Here, we investigated the basis of such strand selectivity by comparing recombination of wild-type and mutated attC sites with different lengths, sequences and structures. We show that all three unpaired structural features that distinguish the bottom and top strands contribute to strand selectivity. The localization of Extra-Helical Bases (EHBs) directly favors integrase binding to the bottom strand. The Unpaired Central Spacer (UCS) and the Variable Terminal Structure (VTS) influence strand selectivity indirectly, probably through the stabilization of the bottom strand and the resulting synapse due to the nucleotide skew between the two strands. These results underscore the importance of the single-stranded nature of the attC site that allows such tight control over integron cassette orientation. Oxford University Press 2016-09-19 2016-08-05 /pmc/articles/PMC5027507/ /pubmed/27496283 http://dx.doi.org/10.1093/nar/gkw646 Text en © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research. http://creativecommons.org/licenses/by-nc/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com |
spellingShingle | Molecular Biology Nivina, Aleksandra Escudero, José Antonio Vit, Claire Mazel, Didier Loot, Céline Efficiency of integron cassette insertion in correct orientation is ensured by the interplay of the three unpaired features of attC recombination sites |
title | Efficiency of integron cassette insertion in correct orientation is ensured by the interplay of the three unpaired features of attC recombination sites |
title_full | Efficiency of integron cassette insertion in correct orientation is ensured by the interplay of the three unpaired features of attC recombination sites |
title_fullStr | Efficiency of integron cassette insertion in correct orientation is ensured by the interplay of the three unpaired features of attC recombination sites |
title_full_unstemmed | Efficiency of integron cassette insertion in correct orientation is ensured by the interplay of the three unpaired features of attC recombination sites |
title_short | Efficiency of integron cassette insertion in correct orientation is ensured by the interplay of the three unpaired features of attC recombination sites |
title_sort | efficiency of integron cassette insertion in correct orientation is ensured by the interplay of the three unpaired features of attc recombination sites |
topic | Molecular Biology |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5027507/ https://www.ncbi.nlm.nih.gov/pubmed/27496283 http://dx.doi.org/10.1093/nar/gkw646 |
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