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

By Alexander M. Geller, Inbal Pollin, David Zlotkin, A. Danov, Nimrod Nachmias, William B. Andreopoulos, K. Shemesh, Asaf Levy. 2020

57 citations recorded by the source corpus.

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.

Subfields: Endocrinology, Infectious Diseases, Molecular Biology

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Citations in the corpus

• Programmable protein delivery with a bacterial contractile injection system (2023, positive): “This experiment is notable because Cas9 is much larger than the payloads natively loaded by this PVC (170 kDa for Pdp1-NTD–Cas9 versus 37 kDa for Pdp1 and Pnf), demonstrating that PVCs can deliver diverse payloads of varying sizes (supporting similar conclusions from other studies 3,22 ).”
• N-terminal signal peptides facilitate the engineering of PVC complex as a potent protein delivery system (2022, unknown): “In the field of T6SS, which have great structure similarities with PVC and other eCIS complexes (43), several types of mechanisms have been determined in assisting the effector secretion.”