Different genetic and morphological outcomes for phages targeted by single or multiple CRISPR-Cas spacers
| Autor: | Raymond H.J. Staals, Bridget N.J. Watson, B. Tong, Peter C. Fineran, Mihnea Bostina, Matthias Wolf, George P. C. Salmond, Richard A. Easingwood |
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| Přispěvatelé: | Salmond, George [0000-0002-5197-2198], Apollo - University of Cambridge Repository |
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Tape measure protein
biology Pectobacterium Computational biology Articles Phage evolution Phage morphology Acquired immune system biology.organism_classification Genome Microbiology General Biochemistry Genetics and Molecular Biology Microbiologie CRISPR Point Mutation Bacteriophages CRISPR-Cas Systems CRISPR-Cas General Agricultural and Biological Sciences Bacteria Archaea VLAG |
| Zdroj: | Philos Trans R Soc Lond B Biol Sci Philosophical Transactions of the Royal Society B: Biological Sciences 374 (2019) 1772 Philosophical Transactions of the Royal Society B: Biological Sciences, 374(1772) |
| ISSN: | 0962-8436 |
| Popis: | CRISPR-Cas systems provide bacteria and archaea with adaptive immunity against genetic invaders, such as bacteriophages. The systems integrate short sequences from the phage genome into the bacterial CRISPR array. These ‘spacers’ provide sequence-specific immunity but drive natural selection of evolved phage mutants that escape the CRISPR-Cas defence. Spacer acquisition occurs by either naive or primed adaptation. Naive adaptation typically results in the incorporation of a single spacer. By contrast, priming is a positive feedback loop that often results in acquisition of multiple spacers, which occurs when a pre-existing spacer matches the invading phage. We predicted that single and multiple spacers, representative of naive and primed adaptation, respectively, would cause differing outcomes after phage infection. We investigated the response of two phages, ϕTE and ϕM1, to the Pectobacterium atrosepticum type I-F CRISPR-Cas system and observed that escape from single spacers typically occurred via point mutations. Alternatively, phages escaped multiple spacers through deletions, which can occur in genes encoding structural proteins. Cryo-EM analysis of the ϕTE structure revealed shortened tails in escape mutants with tape measure protein deletions. We conclude that CRISPR-Cas systems can drive phage genetic diversity, altering morphology and fitness, through selective pressures arising from naive and primed acquisition events. This article is part of a discussion meeting issue ‘The ecology and evolution of prokaryotic CRISPR-Cas adaptive immune systems’. |
| Databáze: | OpenAIRE |
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