Metis system

Edge evidence

• Metis locus contributes to modified mononucleotide sensing RO:0002326

  Metis loci directly sense m6dAMP after phage-mediated host-genome degradation.

  • DOI:10.1126/science.aed6782 In this work, we describe Metis, a bacterial defense system that directly senses phage-mediated host genome degradation. Osterman et al. directly name Metis as a bacterial system sensing host-genome degradation during phage infection.
  • https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md | Metis | 10\.1101/2025\.11\.05\.686725 | Bacteria sense virus-induced genome degradation via methylated mononucleotides | The pinned DefenseFinder article registry maps the named Metis system to the Osterman et al. preprint.
• phage-mediated host genome degradation contributes to modified mononucleotide sensing RO:0002326

  Accumulation of free m6dAMP after host-genome degradation provides the modified mononucleotide signal detected by Metis.

  • DOI:10.1126/science.aed6782 Metis aborts phage infection once it detects the modified mononucleotide N6-methyl-deoxyadenosine monophosphate (m6dAMP). As methylation of deoxyadenosines usually occurs on the DNA polymer, accumulation of m6dAMP signals that the host genome has been degraded. Osterman et al. connect Metis detection of m6dAMP to the accumulation of that nucleotide after host-genome degradation.
  • DOI:10.1126/science.aed6782 We further show that Metis defense depends on endogenous DNA methylases and that phages can escape Metis through mutations that inactivate host genome degradation. Osterman et al. link Metis immunity to endogenous DNA methylases and to phage genome-degradation activity.
• modified mononucleotide sensing activates type-specific toxic effector activation RO:0002213

  m6dAMP sensing activates a Metis type-specific toxic effector.

  • DOI:10.1126/science.aed6782 In type I Metis, sensing of m6dAMP activates a nicotinamide adenine dinucleotide (NAD+) diphosphatase, leading to NAD+ depletion and cessation of the infection process, whereas the effector in type II Metis is a membrane-spanning protein whose toxicity is triggered in response to the modified mononucleotide. Osterman et al. distinguish type I and type II Metis effectors without resolving a DefenseFinder rule-level model in the pinned registry.
• type-specific toxic effector activation confers Metis system METPO:2007700

  Triggered Metis effector toxicity realizes the Metis system trait by aborting phage infection.

  • DOI:10.1126/science.aed6782 Metis aborts phage infection once it detects the modified mononucleotide N6-methyl-deoxyadenosine monophosphate (m6dAMP). Osterman et al. connect m6dAMP sensing to type-specific effector toxicity and abortion of the phage infection process.
• Metis system is a phage defense system rdfs:subClassOf

  Metis system possession is a phage-defense-system trait.

  • DOI:10.1126/science.aed6782 In this work, we describe Metis, a bacterial defense system that directly senses phage-mediated host genome degradation. Metis aborts phage infection once it detects the modified mononucleotide N6-methyl-deoxyadenosine monophosphate (m6dAMP). Osterman et al. identify Metis as a bacterial defense system that aborts phage infection after sensing m6dAMP.