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Enteric Chromosomal Islands: DNA Packaging Specificity and Role of λ-like Helper Phage Terminase

The phage-inducible chromosomal islands (PICIs) of Gram-negative bacteria are analogous to defective prophages that have lost the ability to propagate without the aid of a helper phage. PICIs have acquired genes that alter the genetic repertoire of the bacterial host, including supplying virulence f...

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Autores principales: Murialdo, Helios, Feiss, Michael
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9026076/
https://www.ncbi.nlm.nih.gov/pubmed/35458547
http://dx.doi.org/10.3390/v14040818
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author Murialdo, Helios
Feiss, Michael
author_facet Murialdo, Helios
Feiss, Michael
author_sort Murialdo, Helios
collection PubMed
description The phage-inducible chromosomal islands (PICIs) of Gram-negative bacteria are analogous to defective prophages that have lost the ability to propagate without the aid of a helper phage. PICIs have acquired genes that alter the genetic repertoire of the bacterial host, including supplying virulence factors. Recent work by the Penadés laboratory elucidates how a helper phage infection or prophage induction induces the island to excise from the bacterial chromosome, replicate, and become packaged into functional virions. PICIs lack a complete set of morphogenetic genes needed to construct mature virus particles. Rather, PICIs hijack virion assembly functions from an induced prophage acting as a helper phage. The hijacking strategy includes preventing the helper phage from packaging its own DNA while enabling PICI DNA packaging. In the case of recently described Gram-negative PICIs, the PICI changes the specificity of DNA packaging. This is achieved by an island-encoded protein (Rpp) that binds to the phage protein (TerS), which normally selects phage DNA for packaging from a DNA pool that includes the helper phage and host DNAs. The Rpp–TerS interaction prevents phage DNA packaging while sponsoring PICI DNA packaging. Our communication reviews published data about the hijacking mechanism and its implications for phage DNA packaging. We propose that the Rpp–TerS complex binds to a site in the island DNA that is positioned analogous to that of the phage DNA but has a completely different sequence. The critical role of TerS in the Rpp–TerS complex is to escort TerL to the PICI cosN, ensuring appropriate DNA cutting and packaging.
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spelling pubmed-90260762022-04-23 Enteric Chromosomal Islands: DNA Packaging Specificity and Role of λ-like Helper Phage Terminase Murialdo, Helios Feiss, Michael Viruses Hypothesis The phage-inducible chromosomal islands (PICIs) of Gram-negative bacteria are analogous to defective prophages that have lost the ability to propagate without the aid of a helper phage. PICIs have acquired genes that alter the genetic repertoire of the bacterial host, including supplying virulence factors. Recent work by the Penadés laboratory elucidates how a helper phage infection or prophage induction induces the island to excise from the bacterial chromosome, replicate, and become packaged into functional virions. PICIs lack a complete set of morphogenetic genes needed to construct mature virus particles. Rather, PICIs hijack virion assembly functions from an induced prophage acting as a helper phage. The hijacking strategy includes preventing the helper phage from packaging its own DNA while enabling PICI DNA packaging. In the case of recently described Gram-negative PICIs, the PICI changes the specificity of DNA packaging. This is achieved by an island-encoded protein (Rpp) that binds to the phage protein (TerS), which normally selects phage DNA for packaging from a DNA pool that includes the helper phage and host DNAs. The Rpp–TerS interaction prevents phage DNA packaging while sponsoring PICI DNA packaging. Our communication reviews published data about the hijacking mechanism and its implications for phage DNA packaging. We propose that the Rpp–TerS complex binds to a site in the island DNA that is positioned analogous to that of the phage DNA but has a completely different sequence. The critical role of TerS in the Rpp–TerS complex is to escort TerL to the PICI cosN, ensuring appropriate DNA cutting and packaging. MDPI 2022-04-15 /pmc/articles/PMC9026076/ /pubmed/35458547 http://dx.doi.org/10.3390/v14040818 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Hypothesis
Murialdo, Helios
Feiss, Michael
Enteric Chromosomal Islands: DNA Packaging Specificity and Role of λ-like Helper Phage Terminase
title Enteric Chromosomal Islands: DNA Packaging Specificity and Role of λ-like Helper Phage Terminase
title_full Enteric Chromosomal Islands: DNA Packaging Specificity and Role of λ-like Helper Phage Terminase
title_fullStr Enteric Chromosomal Islands: DNA Packaging Specificity and Role of λ-like Helper Phage Terminase
title_full_unstemmed Enteric Chromosomal Islands: DNA Packaging Specificity and Role of λ-like Helper Phage Terminase
title_short Enteric Chromosomal Islands: DNA Packaging Specificity and Role of λ-like Helper Phage Terminase
title_sort enteric chromosomal islands: dna packaging specificity and role of λ-like helper phage terminase
topic Hypothesis
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9026076/
https://www.ncbi.nlm.nih.gov/pubmed/35458547
http://dx.doi.org/10.3390/v14040818
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