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The evolution of a counter-defense mechanism in a virus constrains its host range
Bacteria use diverse immunity mechanisms to defend themselves against their viral predators, bacteriophages. In turn, phages can acquire counter-defense systems, but it remains unclear how such mechanisms arise and what factors constrain viral evolution. Here, we experimentally evolved T4 phage to o...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
eLife Sciences Publications, Ltd
2022
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9391042/ https://www.ncbi.nlm.nih.gov/pubmed/35924892 http://dx.doi.org/10.7554/eLife.79549 |
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author | Srikant, Sriram Guegler, Chantal K Laub, Michael T |
author_facet | Srikant, Sriram Guegler, Chantal K Laub, Michael T |
author_sort | Srikant, Sriram |
collection | PubMed |
description | Bacteria use diverse immunity mechanisms to defend themselves against their viral predators, bacteriophages. In turn, phages can acquire counter-defense systems, but it remains unclear how such mechanisms arise and what factors constrain viral evolution. Here, we experimentally evolved T4 phage to overcome a phage-defensive toxin-antitoxin system, toxIN, in Escherichia coli. Through recombination, T4 rapidly acquires segmental amplifications of a previously uncharacterized gene, now named tifA, encoding an inhibitor of the toxin, ToxN. These amplifications subsequently drive large deletions elsewhere in T4’s genome to maintain a genome size compatible with capsid packaging. The deleted regions include accessory genes that help T4 overcome defense systems in alternative hosts. Thus, our results reveal a trade-off in viral evolution; the emergence of one counter-defense mechanism can lead to loss of other such mechanisms, thereby constraining host range. We propose that the accessory genomes of viruses reflect the integrated evolutionary history of the hosts they infected. |
format | Online Article Text |
id | pubmed-9391042 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | eLife Sciences Publications, Ltd |
record_format | MEDLINE/PubMed |
spelling | pubmed-93910422022-08-20 The evolution of a counter-defense mechanism in a virus constrains its host range Srikant, Sriram Guegler, Chantal K Laub, Michael T eLife Evolutionary Biology Bacteria use diverse immunity mechanisms to defend themselves against their viral predators, bacteriophages. In turn, phages can acquire counter-defense systems, but it remains unclear how such mechanisms arise and what factors constrain viral evolution. Here, we experimentally evolved T4 phage to overcome a phage-defensive toxin-antitoxin system, toxIN, in Escherichia coli. Through recombination, T4 rapidly acquires segmental amplifications of a previously uncharacterized gene, now named tifA, encoding an inhibitor of the toxin, ToxN. These amplifications subsequently drive large deletions elsewhere in T4’s genome to maintain a genome size compatible with capsid packaging. The deleted regions include accessory genes that help T4 overcome defense systems in alternative hosts. Thus, our results reveal a trade-off in viral evolution; the emergence of one counter-defense mechanism can lead to loss of other such mechanisms, thereby constraining host range. We propose that the accessory genomes of viruses reflect the integrated evolutionary history of the hosts they infected. eLife Sciences Publications, Ltd 2022-08-04 /pmc/articles/PMC9391042/ /pubmed/35924892 http://dx.doi.org/10.7554/eLife.79549 Text en © 2022, Srikant, Guegler et al https://creativecommons.org/licenses/by/4.0/This article is distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use and redistribution provided that the original author and source are credited. |
spellingShingle | Evolutionary Biology Srikant, Sriram Guegler, Chantal K Laub, Michael T The evolution of a counter-defense mechanism in a virus constrains its host range |
title | The evolution of a counter-defense mechanism in a virus constrains its host range |
title_full | The evolution of a counter-defense mechanism in a virus constrains its host range |
title_fullStr | The evolution of a counter-defense mechanism in a virus constrains its host range |
title_full_unstemmed | The evolution of a counter-defense mechanism in a virus constrains its host range |
title_short | The evolution of a counter-defense mechanism in a virus constrains its host range |
title_sort | evolution of a counter-defense mechanism in a virus constrains its host range |
topic | Evolutionary Biology |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9391042/ https://www.ncbi.nlm.nih.gov/pubmed/35924892 http://dx.doi.org/10.7554/eLife.79549 |
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