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Phage integration alters the respiratory strategy of its host
- Source :
- eLife, Vol 8 (2019), eLife
- Publication Year :
- 2019
- Publisher :
- eLife Sciences Publications Ltd, 2019.
-
Abstract
- Temperate bacteriophages are viruses that can incorporate their genomes into their bacterial hosts, existing there as prophages that refrain from killing the host cell until induced. Prophages are largely quiescent, but they can alter host phenotype through factors encoded in their genomes (often virulence factors) or by disrupting host genes as a result of integration. Here we describe another mechanism by which a prophage can modulate host phenotype. We show that a temperate phage that integrates in Escherichia coli reprograms host regulation of an anaerobic respiratory system, thereby inhibiting a bet hedging strategy. The phage exerts this effect by upregulating a host-encoded signal transduction protein through transcription initiated from a phage-encoded promoter. We further show that this phenomenon occurs not only in a laboratory strain of E. coli, but also in a natural isolate that contains a prophage at this site.<br />eLife digest Animals and plants can all fall prey to viruses – and so can bacteria. The viruses that infect bacteria are called bacteriophages (or phages for short), and they are found everywhere bacteria live and probably outnumber bacteria by at least ten to one. While some phages quickly kill every bacterial cell they infect, others enter a dormant state by inserting their DNA into the DNA of their host cell. Here they lie in wait for a signal that reactivates them, triggering the production of more phages and the death of the host cell. While the phage lies dormant its DNA may harm the host by interfering with nearby bacterial genes, or it may actually provide new genes that benefit the host. In most cases the effects of dormant phages are unknown. A bacterium known as Escherichia coli is commonly found in the intestines of humans and other mammals. It can use a nutrient called trimethylamine oxide (TMAO) to help it survive rapid decreases in oxygen levels that can occur in its environment. When a phage called HK022 infects E. coli, the phage enters a dormant state by inserting its DNA between two genes that are critical for E. coli to use TMAO. However, it is not clear what effect, if any, HK022 has on E. coli’s behavior. To address this question, Carey et al. used genetic approaches to study E. coli cells carrying dormant HK022 phages. The experiments showed that the bacteria lost the ability to use TMAO to survive rapid decreases in oxygen because the dormant phages switched on one of the neighboring E. coli genes. Unexpectedly, the phage achieved this by neatly replacing the gene’s own promoter – the stretch of DNA that contains information about when the gene should be switched on, and how strongly – with a substitute promoter carried in the phage’s DNA. This substitute promoter is stronger than the normal version – meaning that the gene is more active than it should be. Phages are key players in every natural population of microbes and are therefore entwined in the health of humans and the environment. The findings of Carey et al. show a new mechanism through which phages modify their hosts. In the future it may be possible to develop this mechanism into a tool to manipulate bacteria in complex environments like infection sites, for example by introducing phages that block the mechanisms that allow bacteria to tolerate antibiotics.
- Subjects :
- 0301 basic medicine
QH301-705.5
viruses
Prophages
Virus Integration
Science
030106 microbiology
Biology
medicine.disease_cause
Coliphages
General Biochemistry, Genetics and Molecular Biology
Bacterial cell structure
Microbiology
Bacteriophage
03 medical and health sciences
chemistry.chemical_compound
bacteriophage
Gene expression
medicine
Escherichia coli
Anaerobiosis
Biology (General)
Gene
bet hedging
Microbiology and Infectious Disease
General Immunology and Microbiology
trimethylamine N-oxide
Host (biology)
General Neuroscience
fungi
E. coli
General Medicine
Gene Expression Regulation, Bacterial
biology.organism_classification
Chromosomes and Gene Expression
030104 developmental biology
chemistry
Medicine
two-component signaling
Energy Metabolism
DNA
Bacteria
Signal Transduction
Research Article
Subjects
Details
- Language :
- English
- Volume :
- 8
- Database :
- OpenAIRE
- Journal :
- eLife
- Accession number :
- edsair.doi.dedup.....a7174a6a316c995335d3b20cabf0c5c6