REVIEW: Microbial Arsenal of Antiviral Defenses – Part I

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Artem B. Isaev^1,a*, Olga S. Musharova^1,2,b, and Konstantin V. Severinov^1,3,c*

¹Skolkovo Institute of Science and Technology, 143028 Moscow, Russia

²Institute of Molecular Genetics, 119334 Moscow, Russia

³Waksman Institute of Microbiology, Piscataway, NJ 08854, USA

^* To whom correspondence should be addressed.

Received August 10, 2020; Revised August 18, 2020; Accepted September 12, 2020

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Bacteriophages or phages are viruses that infect bacterial cells (for the scope of this review we will also consider viruses that infect Archaea). Constant threat of phage infection is a major force that shapes evolution of the microbial genomes. To withstand infection, bacteria had evolved numerous strategies to avoid recognition by phages or to directly interfere with phage propagation inside the cell. Classical molecular biology and genetic engineering have been deeply intertwined with the study of phages and host defenses. Nowadays, owing to the rise of phage therapy, broad application of CRISPR-Cas technologies, and development of bioinformatics approaches that facilitate discovery of new systems, phage biology experiences a revival. This review describes variety of strategies employed by microbes to counter phage infection, with a focus on novel systems discovered in recent years. First chapter covers defense associated with cell surface, role of small molecules, and innate immunity systems relying on DNA modification.

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KEY WORDS: bacteriophages, phage–host interactions, antiviral defense, immunity systems, CRISPR-Cas, restriction–modification, BREX, DISARM, phosphorothioate, Dnd systems

DOI: 10.1134/S0006297921030081

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