identifier: traitmech:000273 label: DARNA system definition: A phage defense system in which activated DARNA cleaves a subset of host tRNAs and thereby inhibits phage propagation after activation by single-stranded DNA presented by phage SSB. definition_source: DOI:10.64898/2026.02.22.705581 trait_category: GENOMICS term_kind: CLASS mapping_status: PROPOSED parent_traits: - traitmech:000209 synonyms: - synonym_text: DARNA synonym_type: EXACT_SYNONYM source: DOI:10.64898/2026.02.22.705581 evidence: - reference: DOI:10.64898/2026.02.22.705581 snippet: the bacterial immunity protein DARNA, once activated, cleaves a subset of host tRNAs, thereby inhibiting phage propagation notes: Puteikiene et al. support DARNA as a bacterial immunity protein whose activation leads to host tRNA cleavage and phage-propagation inhibition. - reference: DOI:10.64898/2026.02.22.705581 snippet: DARNA is activated by single-stranded DNA presented by phage SSB, but not by the host SSB notes: Puteikiene et al. support phage SSB-presented single-stranded DNA as an activation input for DARNA. - reference: DOI:10.64898/2026.02.22.705581 snippet: The recognition of an endogenous nucleic acid signal promoted by a viral protein ensures that DARNA can detect and respond to a broad range of viruses while avoiding auto-immunity notes: Puteikiene et al. connect DARNA activation to viral-protein promoted self/non-self discrimination. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: DARNA | 10\.64898/2026\.02\.22\.705581 | Viral SSB-bound ssDNA activates the bacterial anti-phage defense system DARNA notes: The DefenseFinder article registry maps the named DARNA system to the Puteikiene et al. bacterial anti-phage-system preprint. causal_graphs: - graph_id: darna_phage_ssb_ssdna_cleaves_trna title: DARNA activation restricts phage propagation through host-tRNA cleavage description: Process sketch linking phage SSB-presented single-stranded DNA to DARNA activation, cleavage of a subset of host tRNAs, restricted phage propagation, and the DARNA system trait. scope_status: NONMECHANISTIC scope_notes: The graph captures the DOI abstract's DARNA activation and tRNA-cleavage summary without asserting a DefenseFinder component profile, universal locus architecture, strain-resolved component accessions, or the full host and phage breadth of every natural DARNA system. nodes: - node_id: phage_ssb_presented_ssdna label: phage SSB-presented single-stranded DNA node_type: BIOLOGICAL_PROCESS description: Presentation of single-stranded DNA by phage single-stranded DNA-binding protein rather than by host SSB. - node_id: darna_activation label: DARNA activation node_type: BIOLOGICAL_PROCESS description: Activation of the bacterial immunity protein DARNA by phage SSB-presented single-stranded DNA. - node_id: host_trna_cleavage label: host tRNA cleavage node_type: BIOLOGICAL_PROCESS description: Cleavage of a subset of host tRNAs after DARNA is activated. - node_id: restricted_phage_propagation label: restricted phage propagation node_type: BIOLOGICAL_PROCESS description: Reduced propagation of bacteriophage after DARNA activation and host-tRNA cleavage. - node_id: darna_system_trait label: DARNA system node_type: TRAIT grounding: traitmech:000273 description: Possession of a genome-encoded DARNA 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: phage_ssb_presented_ssdna predicate: triggers object: darna_activation description: Single-stranded DNA presented by phage SSB activates DARNA. evidence: - reference: DOI:10.64898/2026.02.22.705581 snippet: DARNA is activated by single-stranded DNA presented by phage SSB, but not by the host SSB notes: Puteikiene et al. directly identify phage SSB-presented single-stranded DNA as the DARNA activation signal. - subject: darna_activation predicate: contributes to predicate_id: RO:0002326 object: host_trna_cleavage description: Activated DARNA cleaves a subset of host tRNAs. evidence: - reference: DOI:10.64898/2026.02.22.705581 snippet: the bacterial immunity protein DARNA, once activated, cleaves a subset of host tRNAs notes: Puteikiene et al. connect DARNA activation to host-tRNA cleavage. - subject: host_trna_cleavage predicate: contributes to predicate_id: RO:0002326 object: restricted_phage_propagation description: DARNA-dependent host-tRNA cleavage inhibits phage propagation. evidence: - reference: DOI:10.64898/2026.02.22.705581 snippet: cleaves a subset of host tRNAs, thereby inhibiting phage propagation notes: Puteikiene et al. place phage-propagation inhibition downstream of DARNA-mediated host-tRNA cleavage. - subject: restricted_phage_propagation predicate: confers predicate_id: METPO:2007700 object: darna_system_trait description: DARNA-mediated phage-propagation inhibition realizes the DARNA system trait. evidence: - reference: DOI:10.64898/2026.02.22.705581 snippet: DARNA can detect and respond to a broad range of viruses while avoiding auto-immunity notes: Puteikiene et al. support the detected viral signal and antiviral response as the DARNA system output. - subject: darna_system_trait predicate: is a predicate_id: rdfs:subClassOf object: phage_defense_system description: DARNA system possession is a phage-defense-system trait. evidence: - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: DARNA | 10\.64898/2026\.02\.22\.705581 | Viral SSB-bound ssDNA activates the bacterial anti-phage defense system DARNA notes: DefenseFinder associates DARNA with the Puteikiene et al. bacterial anti-phage defense-system preprint. discussions: - discussion_id: darna-model-profile-gap prompt: Resolve DARNA component profiles and locus architecture before minting component-profile synonyms or narrower DARNA subsystem traits. kind: KNOWLEDGE_GAP status: OPEN rationale: Puteikiene et al. support DARNA as an anti-phage system with a resolved phage-SSB single-stranded-DNA trigger and host-tRNA cleavage output, and DefenseFinder lists DARNA in its article registry. The pinned DefenseFinder snapshot does not yet expose DARNA HMM or rule rows, so this first record does not assert a component-profile synonym or universal locus architecture. attaches_to: - causal_graphs#darna_phage_ssb_ssdna_cleaves_trna posed_by: codex posed_date: '2026-09-19' curation_history: - timestamp: '2026-09-19T08:54:19Z' curator: codex action: MINTED_TRAITMECH_ID changes: Minted DARNA system as a DOI-backed GENOMICS TraitRecord under phage defense system 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_v150. llm_assisted: true