Cargando…
Evolution of Superinfection Immunity in Cluster A Mycobacteriophages
Temperate phages encode an immunity system to control lytic gene expression during lysogeny. This gene regulatory circuit consists of multiple interacting genetic elements, and although it is essential for controlling phage growth, it is subject to conflicting evolutionary pressures. During superinf...
Autores principales: | , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Society for Microbiology
2019
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6550527/ https://www.ncbi.nlm.nih.gov/pubmed/31164468 http://dx.doi.org/10.1128/mBio.00971-19 |
_version_ | 1783424199157612544 |
---|---|
author | Mavrich, Travis N. Hatfull, Graham F. |
author_facet | Mavrich, Travis N. Hatfull, Graham F. |
author_sort | Mavrich, Travis N. |
collection | PubMed |
description | Temperate phages encode an immunity system to control lytic gene expression during lysogeny. This gene regulatory circuit consists of multiple interacting genetic elements, and although it is essential for controlling phage growth, it is subject to conflicting evolutionary pressures. During superinfection of a lysogen, the prophage’s circuit interacts with the superinfecting phage’s circuit and prevents lytic growth if the two circuits are closely related. The circuitry is advantageous since it provides the prophage with a defense mechanism, but the circuitry is also disadvantageous since it limits the phage’s host range during superinfection. Evolutionarily related phages have divergent, orthogonal immunity systems that no longer interact and are heteroimmune, but we do not understand how immunity systems evolve new specificities. Here, we use a group of Cluster A mycobacteriophages that exhibit a spectrum of genetic diversity to examine how immunity system evolution impacts superinfection immunity. We show that phages with mesotypic (i.e., genetically related but distinct) immunity systems exhibit asymmetric and incomplete superinfection phenotypes. They form complex immunity networks instead of well-defined immunity groups, and mutations conferring escape (i.e., virulence) from homotypic or mesotypic immunity have various escape specificities. Thus, virulence and the evolution of new immune specificities are shaped by interactions with homotypic and mesotypic immunity systems. |
format | Online Article Text |
id | pubmed-6550527 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | American Society for Microbiology |
record_format | MEDLINE/PubMed |
spelling | pubmed-65505272019-06-14 Evolution of Superinfection Immunity in Cluster A Mycobacteriophages Mavrich, Travis N. Hatfull, Graham F. mBio Research Article Temperate phages encode an immunity system to control lytic gene expression during lysogeny. This gene regulatory circuit consists of multiple interacting genetic elements, and although it is essential for controlling phage growth, it is subject to conflicting evolutionary pressures. During superinfection of a lysogen, the prophage’s circuit interacts with the superinfecting phage’s circuit and prevents lytic growth if the two circuits are closely related. The circuitry is advantageous since it provides the prophage with a defense mechanism, but the circuitry is also disadvantageous since it limits the phage’s host range during superinfection. Evolutionarily related phages have divergent, orthogonal immunity systems that no longer interact and are heteroimmune, but we do not understand how immunity systems evolve new specificities. Here, we use a group of Cluster A mycobacteriophages that exhibit a spectrum of genetic diversity to examine how immunity system evolution impacts superinfection immunity. We show that phages with mesotypic (i.e., genetically related but distinct) immunity systems exhibit asymmetric and incomplete superinfection phenotypes. They form complex immunity networks instead of well-defined immunity groups, and mutations conferring escape (i.e., virulence) from homotypic or mesotypic immunity have various escape specificities. Thus, virulence and the evolution of new immune specificities are shaped by interactions with homotypic and mesotypic immunity systems. American Society for Microbiology 2019-06-04 /pmc/articles/PMC6550527/ /pubmed/31164468 http://dx.doi.org/10.1128/mBio.00971-19 Text en Copyright © 2019 Mavrich and Hatfull. https://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license (https://creativecommons.org/licenses/by/4.0/) . |
spellingShingle | Research Article Mavrich, Travis N. Hatfull, Graham F. Evolution of Superinfection Immunity in Cluster A Mycobacteriophages |
title | Evolution of Superinfection Immunity in Cluster A Mycobacteriophages |
title_full | Evolution of Superinfection Immunity in Cluster A Mycobacteriophages |
title_fullStr | Evolution of Superinfection Immunity in Cluster A Mycobacteriophages |
title_full_unstemmed | Evolution of Superinfection Immunity in Cluster A Mycobacteriophages |
title_short | Evolution of Superinfection Immunity in Cluster A Mycobacteriophages |
title_sort | evolution of superinfection immunity in cluster a mycobacteriophages |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6550527/ https://www.ncbi.nlm.nih.gov/pubmed/31164468 http://dx.doi.org/10.1128/mBio.00971-19 |
work_keys_str_mv | AT mavrichtravisn evolutionofsuperinfectionimmunityinclusteramycobacteriophages AT hatfullgrahamf evolutionofsuperinfectionimmunityinclusteramycobacteriophages |