Effects of mutations in phage restriction sites during escape from restriction–modification Journal Article

Author(s): Pleska, Maros; Guet, Cǎlin C
Article Title: Effects of mutations in phage restriction sites during escape from restriction–modification
Affiliation IST Austria
Abstract: Restriction–modification systems are widespread genetic elements that protect bacteria from bacteriophage infections by recognizing and cleaving heterologous DNA at short, well-defined sequences called restriction sites. Bioinformatic evidence shows that restriction sites are significantly underrepresented in bacteriophage genomes, presumably because bacteriophages with fewer restriction sites are more likely to escape cleavage by restriction–modification systems. However, how mutations in restriction sites affect the likelihood of bacteriophage escape is unknown. Using the bacteriophage l and the restriction–modification system EcoRI, we show that while mutation effects at different restriction sites are unequal, they are independent. As a result, the probability of bacteriophage escape increases with each mutated restriction site. Our results experimentally support the role of restriction site avoidance as a response to selection imposed by restriction–modification systems and offer an insight into the events underlying the process of bacteriophage escape.
Keywords: Mutation effects; phage–bacteria interactions; restriction site avoidance; restriction–modification systems
Journal Title: Biology Letters
Volume: 13
Issue 12
ISSN: 1744-957X
Publisher: Royal Society, The  
Date Published: 2017-12-01
Start Page: Article number: 20170646
Sponsor: HFSP Young Investigators' grant RGY0079/2011; DOC Fellowship of the Austrian Academy of Science
DOI: 10.1098/rsbl.2017.0646
Notes: We thank D. Refardt for the wild-type λ cI857 phage, M. Lang, F. Jesse and members of the C.C.G. laboratory for in-depth discussions.
Open access: no