identifier: traitmech:000211 label: DISARM system definition: A genomics trait describing possession of a Defense Island System Associated with Restriction-Modification locus that uses methyltransferase-associated self/non-self discrimination and DrmAB activation to inhibit bacteriophage DNA replication. definition_source: DOI:10.1038/s41564-017-0051-0 trait_category: GENOMICS term_kind: CLASS mapping_status: PROPOSED parent_traits: - traitmech:000209 synonyms: - synonym_text: Defense Island System Associated with Restriction-Modification synonym_type: EXACT_SYNONYM source: DOI:10.1038/s41467-022-30673-1 - synonym_text: Defense Island System Associated with Restriction Modification synonym_type: EXACT_SYNONYM source: DOI:10.1038/s41467-022-30673-1 evidence: - reference: DOI:10.1038/s41564-017-0051-0 snippet: Our results establish DISARM as a new defence system, providing protection against diverse phages notes: Ofir et al. experimentally established DISARM as a phage defense system and distinguished its intracellular block from phage-adsorption phenotypes. - reference: DOI:10.1038/s41564-017-0051-0 snippet: The DISARM system is widespread in defence islands across the microbial world notes: Ofir et al. support DISARM as a recurring microbial defense island system rather than a single source-specific locus. - reference: DOI:10.1038/s41467-022-30673-1 snippet: DISARM (Defense Island System Associated with Restriction-Modification) systems can provide protection against a wide range of phage notes: Bravo et al. independently expand the DISARM acronym and frame DISARM as a broad anti-phage system. - reference: DOI:10.1038/s41467-022-30673-1 snippet: In vivo studies of structure-guided DrmAB mutants demonstrate that ATP hydrolysis, DNA binding, and DrmAB heterodimer formation are essential for phage targeting by DISARM notes: Bravo et al. support the DrmAB activation mechanism recorded in the first causal graph. canonical_examples: - taxon_id: NCBITaxon:766760 taxon_label: Bacillus paralicheniformis ATCC 9945a note: Ofir et al. amplified the native B. paralicheniformis ATCC 9945a class 2 DISARM locus and integrated it into B. subtilis to test phage defense. reference: DOI:10.1038/s41564-017-0051-0 causal_graphs: - graph_id: disarm_dna_sensing_antiphage_defense title: DISARM senses phage DNA to activate DrmAB defense description: Evidence-backed causal sketch linking DISARM methylation and 5-prime-overhang DNA sensing to DrmAB activation and blocked early phage DNA circularization. scope_status: MECHANISTIC scope_notes: The graph captures host DNA methylation, 5-prime-overhang sensing, DrmAB activation, and early phage DNA restriction without asserting the unresolved downstream nuclease or replication-block coupling. nodes: - node_id: host_dna_methylation label: DISARM host DNA methylation node_type: BIOLOGICAL_PROCESS description: DISARM methyltransferase-mediated methylation of host DNA at cognate motifs. - node_id: five_prime_overhang_dna_sensing label: DISARM 5-prime-overhang DNA sensing node_type: BIOLOGICAL_PROCESS description: DrmAB-associated recognition of foreign DNA substrates carrying a 5-prime single-stranded overhang. - node_id: drmab_core_complex grounding_status: REVIEWED_LABEL_ONLY grounding_notes: DrmA and DrmB are distinct DISARM protein families; this node denotes the activated heterodimeric core complex rather than one component family. label: DrmAB core complex node_type: GENE_OR_PROTEIN description: Heterodimeric DISARM DrmA-DrmB core complex that binds invading DNA and undergoes long-range activation upon 5-prime-overhang substrate loading. gene_symbols: - drmA - drmB operon: DISARM protein_examples: - uniprot_id: UniProtKB:P0DW05 protein_label: DISARM protein DrmA gene_symbol: drmA taxon_id: NCBITaxon:766760 taxon_label: Bacillus paralicheniformis ATCC 9945a entry_status: REVIEWED retrieved_on: '2026-09-15' entry_version: 12 sequence_version: 1 role: B. paralicheniformis ATCC 9945a DrmA is the helicase-domain component of the class 2 DISARM DrmAB core. evidence: - reference: DOI:10.1038/s41564-017-0051-0 snippet: Deletions of drmA (helicase domain), drmB (DUF1998 domain) and drmE (unknown function) abolished DISARM protection against all phages tested notes: Ofir et al. tested scarless deletions in the native B. paralicheniformis ATCC 9945a DISARM locus; UniProt verifies the reviewed DrmA accession. - uniprot_id: UniProtKB:P0DW06 protein_label: DISARM protein DrmB gene_symbol: drmB taxon_id: NCBITaxon:766760 taxon_label: Bacillus paralicheniformis ATCC 9945a entry_status: REVIEWED retrieved_on: '2026-09-15' entry_version: 9 sequence_version: 1 role: B. paralicheniformis ATCC 9945a DrmB is the DUF1998 component paired with DrmA in the class 2 DISARM DrmAB core. evidence: - reference: DOI:10.1038/s41564-017-0051-0 snippet: Deletions of drmA (helicase domain), drmB (DUF1998 domain) and drmE (unknown function) abolished DISARM protection against all phages tested notes: Ofir et al. tested scarless deletions in the native B. paralicheniformis ATCC 9945a DISARM locus; UniProt verifies the reviewed DrmB accession. - node_id: drmab_activation label: DISARM DrmAB activation node_type: BIOLOGICAL_PROCESS description: DNA-triggered activation of the DISARM DrmAB core complex. - node_id: phage_dna_circularization label: phage DNA circularization node_type: BIOLOGICAL_PROCESS description: Circularization of injected bacteriophage genomic DNA after adsorption and DNA entry. - node_id: disarm_system_trait label: DISARM system node_type: TRAIT grounding: traitmech:000211 description: Possession of a genome-encoded DISARM phage defense system. - node_id: phage_defense_system label: phage defense system node_type: TRAIT grounding: traitmech:000209 description: Possession of one or more genome-encoded immune systems that inhibit bacteriophage infection. edges: - subject: drmab_core_complex predicate: contributes to predicate_id: RO:0002326 object: drmab_activation description: DrmA DNA binding, DrmA ATP hydrolysis, and DrmAB heterodimer formation are required for DISARM activation and phage targeting. evidence: - reference: DOI:10.1038/s41467-022-30673-1 snippet: DNA binding, and DrmAB heterodimer formation are essential for phage targeting by DISARM notes: Bravo et al. established the structural and functional importance of the DrmA-DrmB core complex. - subject: host_dna_methylation predicate: negatively regulates predicate_id: RO:0002212 object: drmab_activation description: DISARM host-DNA methylation limits DrmAB activation by self DNA. evidence: - reference: DOI:10.1038/s41467-022-30673-1 snippet: methylated DNA limits the ATPase activity of DrmAB which is essential for anti-phage defense notes: Bravo et al. support methylation-sensitive DrmAB activation as a self/non-self filter. - subject: five_prime_overhang_dna_sensing predicate: activates predicate_id: RO:0002213 object: drmab_activation description: Unmethylated 5-prime-overhang DNA dislodges the DrmA trigger loop to activate DrmAB. evidence: - reference: DOI:10.1038/s41467-022-30673-1 snippet: binding to DNA substrates containing a 5′ overhang dislodges the TL, initiating a long-range structural rearrangement for DrmAB activation notes: Bravo et al. structurally support 5-prime-overhang-triggered DrmAB activation. - subject: drmab_activation predicate: mitigates predicate_id: METPO:2007407 object: phage_dna_circularization description: Activated DISARM blocks early phage DNA circularization and replication after phage entry. evidence: - reference: DOI:10.1038/s41564-017-0051-0 snippet: phi3T was not able to circularize its genome or form detectible lysogens in DISARM-containing cells notes: Ofir et al. showed that DISARM blocks an early intracellular step after phage adsorption. - subject: drmab_activation predicate: confers predicate_id: METPO:2007700 object: disarm_system_trait description: DrmAB activation realizes DISARM-mediated anti-phage defense. evidence: - reference: DOI:10.1038/s41467-022-30673-1 snippet: provide the mechanism of targeting a wide range of phage by DISARM notes: Bravo et al. linked DNA-interacting DrmA residues to DISARM anti-phage protection in vivo. - subject: disarm_system_trait predicate: is a predicate_id: rdfs:subClassOf object: phage_defense_system description: DISARM possession is a methyltransferase-associated phage-defense-system trait. evidence: - reference: DOI:10.1038/s41564-017-0051-0 snippet: Our results establish DISARM as a new defence system notes: Ofir et al. establish DISARM in the phage defense system family. discussions: - discussion_id: disarm-downstream-effector-gap prompt: Resolve the downstream nuclease or replication-blocking effector coupled to activated DrmAB before adding a more specific DISARM phage-DNA degradation edge. kind: KNOWLEDGE_GAP status: OPEN rationale: Ofir et al. inferred phage DNA degradation and showed that DrmC is partially redundant across phages; Bravo et al. resolved DrmAB recognition and activation but left the downstream nuclease or physical replication block as a model. posed_by: codex posed_date: '2026-09-15' curation_history: - timestamp: '2026-09-15T09:40:00Z' curator: codex action: MINTED_TRAITMECH_ID changes: Minted DISARM system as a DOI-backed GENOMICS TraitRecord under the phage defense system parent with reviewed B. paralicheniformis ATCC 9945a DrmA and DrmB protein examples after an ignored-and-hidden duplicate review found no exact live TraitMech, METPO, or prior proposal record; the replacement placeholder is reserved in proposals/metpo_traitmech_v88. llm_assisted: true