The extracellular contractile injection system is enriched in environmental microbes and associates with numerous toxins

• Published in: Nature communications Vol. 12; no. 1; p. 3743
• Main Authors: Geller, Alexander Martin, Pollin, Inbal, Zlotkin, David, Danov, Aleks, Nachmias, Nimrod, Andreopoulos, William B., Shemesh, Keren, Levy, Asaf
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 18.06.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 631/158/2452; 631/208/191; 631/208/325/2482; 631/326/41/1319; 82/80; Animals; Antiinfectives and antibacterials; Archaea - genetics; Archaea - metabolism; Bacteria; Bacteria - genetics; Bacteria - metabolism; Bacteriophages - metabolism; Contractile Proteins - genetics; Contractility; Enrichment; Eukaryotes; Fungi; Genes; Genomes; Humanities and Social Sciences; Injection; Intoxication; Invertebrates; Loci; Microorganisms; multidisciplinary; Nematoda; Phages; Prokaryotes; Protein Translocation Systems - genetics; Protein Translocation Systems - metabolism; Protein Transport - physiology; Science; Science (multidisciplinary); Toxins; Toxins, Biological - genetics; Toxins, Biological - metabolism; Transcription; Yeast; Yeasts
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-23777-7

The extracellular Contractile Injection System (eCIS) is a toxin-delivery particle that evolved from a bacteriophage tail. Four eCISs have previously been shown to mediate interactions between bacteria and their invertebrate hosts. Here, we identify eCIS loci in 1,249 bacterial and archaeal genomes and reveal an enrichment of these loci in environmental microbes and their apparent absence from mammalian pathogens. We show that 13 eCIS-associated toxin genes from diverse microbes can inhibit the growth of bacteria and/or yeast. We identify immunity genes that protect bacteria from self-intoxication, further supporting an antibacterial role for some eCISs. We also identify previously undescribed eCIS core genes, including a conserved eCIS transcriptional regulator. Finally, we present our data through an extensive eCIS repository, termed eCIStem. Our findings support eCIS as a toxin-delivery system that is widespread among environmental prokaryotes and likely mediates antagonistic interactions with eukaryotes and other prokaryotes. The extracellular Contractile Injection System (eCIS) is a toxin-delivery particle that mediates interactions between bacteria and their invertebrate hosts. Here, the authors catalogue eCIS loci from 1,249 prokaryotic genomes, showing enrichment in non-pathogenic environmental microbes, and identifying eCIS-associated toxins that inhibit the growth of bacteria and/or yeast.