Incomplete prophage tolerance by type III-A CRISPR-Cas systems reduces the fitness of lysogenic hosts.
Nat Commun
; 9(1): 61, 2018 01 04.
Article
em En
| MEDLINE
| ID: mdl-29302058
ABSTRACT
CRISPR-Cas systems offer an immune mechanism through which prokaryotic hosts can acquire heritable resistance to genetic parasites, including temperate phages. Co-transcriptional DNA and RNA targeting by type III-A CRISPR-Cas systems restricts temperate phage lytic infections while allowing lysogenic infections to be tolerated under conditions where the prophage targets are transcriptionally repressed. However, long-term consequences of this phenomenon have not been explored. Here we show that maintenance of conditionally tolerant type III-A systems can produce fitness costs within populations of Staphylococcus aureus lysogens. The fitness costs depend on the activity of prophage-internal promoters and type III-A Cas nucleases implicated in targeting, can be more severe in double lysogens, and are alleviated by spacer-target mismatches which do not abrogate immunity during the lytic cycle. These findings suggest that persistence of type III-A systems that target endogenous prophages could be enhanced by spacer-target mismatches, particularly among populations that are prone to polylysogenization.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Staphylococcus aureus
/
Staphylococcus epidermidis
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Bacteriófagos
/
Viroses
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Prófagos
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Sistemas CRISPR-Cas
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Lisogenia
Idioma:
En
Revista:
Nat Commun
Assunto da revista:
BIOLOGIA
/
CIENCIA
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
Estados Unidos