Beyond the CRISPR-Cas safeguard: PICI-encoded innate immune systems protect bacteria from bacteriophage predation. (August 2020)

• Record Type: Journal Article
• Authors: Fillol-Salom, Alfred; Miguel-Romero, Laura; Marina, Alberto; Chen, John; Penadés, José R
• Is Part Of: Current opinion in microbiology. Volume 56(2020)
• Page Start: 52
• Page End: 58
• Publication Date: 2020-08
• Subjects: Microbiology -- Periodicals; 579.05
• DOI: 10.1016/j.mib.2020.06.002
• Languages: English
• ISSNs: 1369-5274

Abstract

Highlights: Phage satellites have evolved multiple and convergent strategies to inhibit phage reproduction. Production of small phage capsids is a universal mechanism used by satellite phages to inhibit phage maturation. Satellite phages have evolved mechanisms that promote their own packaging and transfer. Abstract : Phage satellites are genetic elements that depend on helper phages for induction, packaging and transfer. To promote their lifestyles, they have evolved elegant and sophisticated strategies to inhibit phage reproduction, which will be reviewed here. We will principally focus on the convergent interference mechanisms used by phage-inducible chromosomal islands (PICIs), which are a family of satellite phages present in both Gram-positive and Gram-negative bacteria. While some PICI elements have been extensively studied for their roles in virulence and antibiotic resistance, recent studies have highlighted their relevance in controlling phage ecology and diversity. In many cases, these interference mechanisms are complemented by additional strategies that promote the preferential PICI packaging and dissemination of these elements in nature. Since the PICI-encoded mechanisms target conserved phage mechanisms, we propose here that the PICIs form part of the initial innate immune system that phages must overcome to infect their bacterial host.