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Co-evolution within structured bacterial communities results in multiple expansion of CRISPR loci and enhanced immunity

Type II CRISPR-Cas systems provide immunity against phages and plasmids that infect bacteria through the insertion of a short sequence from the invader’s genome, known as the ‘spacer’, into the CRISPR locus. Spacers are transcribed into guide RNAs that direct the Cas9 nuclease to its target on the i...

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Detalles Bibliográficos
Autores principales: Pyenson, Nora C, Marraffini, Luciano A
Formato: Online Artículo Texto
Lenguaje:English
Publicado: eLife Sciences Publications, Ltd 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7105378/
https://www.ncbi.nlm.nih.gov/pubmed/32223887
http://dx.doi.org/10.7554/eLife.53078
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author Pyenson, Nora C
Marraffini, Luciano A
author_facet Pyenson, Nora C
Marraffini, Luciano A
author_sort Pyenson, Nora C
collection PubMed
description Type II CRISPR-Cas systems provide immunity against phages and plasmids that infect bacteria through the insertion of a short sequence from the invader’s genome, known as the ‘spacer’, into the CRISPR locus. Spacers are transcribed into guide RNAs that direct the Cas9 nuclease to its target on the invader. In liquid cultures, most bacteria acquire a single spacer. Multiple spacer integration is a rare event which significance for immunity is poorly understood. Here, we found that when phage infections occur on solid media, a high proportion of the surviving colonies display complex morphologies that contain cells with multiple spacers. This is the result of the viral-host co-evolution, in which the immunity provided by the initial acquired spacer is easily overcome by escaper phages. Our results reveal the versatility of CRISPR-Cas immunity, which can respond with both single or multiple spacer acquisition schemes to solve challenges presented by different environments.
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spelling pubmed-71053782020-04-01 Co-evolution within structured bacterial communities results in multiple expansion of CRISPR loci and enhanced immunity Pyenson, Nora C Marraffini, Luciano A eLife Microbiology and Infectious Disease Type II CRISPR-Cas systems provide immunity against phages and plasmids that infect bacteria through the insertion of a short sequence from the invader’s genome, known as the ‘spacer’, into the CRISPR locus. Spacers are transcribed into guide RNAs that direct the Cas9 nuclease to its target on the invader. In liquid cultures, most bacteria acquire a single spacer. Multiple spacer integration is a rare event which significance for immunity is poorly understood. Here, we found that when phage infections occur on solid media, a high proportion of the surviving colonies display complex morphologies that contain cells with multiple spacers. This is the result of the viral-host co-evolution, in which the immunity provided by the initial acquired spacer is easily overcome by escaper phages. Our results reveal the versatility of CRISPR-Cas immunity, which can respond with both single or multiple spacer acquisition schemes to solve challenges presented by different environments. eLife Sciences Publications, Ltd 2020-03-30 /pmc/articles/PMC7105378/ /pubmed/32223887 http://dx.doi.org/10.7554/eLife.53078 Text en © 2020, Pyenson and Marraffini http://creativecommons.org/licenses/by/4.0/ http://creativecommons.org/licenses/by/4.0/This article is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use and redistribution provided that the original author and source are credited.
spellingShingle Microbiology and Infectious Disease
Pyenson, Nora C
Marraffini, Luciano A
Co-evolution within structured bacterial communities results in multiple expansion of CRISPR loci and enhanced immunity
title Co-evolution within structured bacterial communities results in multiple expansion of CRISPR loci and enhanced immunity
title_full Co-evolution within structured bacterial communities results in multiple expansion of CRISPR loci and enhanced immunity
title_fullStr Co-evolution within structured bacterial communities results in multiple expansion of CRISPR loci and enhanced immunity
title_full_unstemmed Co-evolution within structured bacterial communities results in multiple expansion of CRISPR loci and enhanced immunity
title_short Co-evolution within structured bacterial communities results in multiple expansion of CRISPR loci and enhanced immunity
title_sort co-evolution within structured bacterial communities results in multiple expansion of crispr loci and enhanced immunity
topic Microbiology and Infectious Disease
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7105378/
https://www.ncbi.nlm.nih.gov/pubmed/32223887
http://dx.doi.org/10.7554/eLife.53078
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