identifier: traitmech:000537 label: Avs IV system definition: An AVAST system in which an organism possesses a genome-encoded subtype IV locus represented by DefenseFinder with an Avs4A profile. definition_source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv trait_category: GENOMICS term_kind: CLASS mapping_status: PROPOSED parent_traits: - traitmech:000239 synonyms: - synonym_text: Avs_IV synonym_type: RELATED_SYNONYM source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv - synonym_text: Avs_IV__Avs4A synonym_type: RELATED_SYNONYM source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md evidence: - reference: DOI:10.1126/science.aba0372 snippet: AVAST, antiviral ATPase/NTPase of the STAND superfamily notes: Gao et al. coined AVAST as an antiviral STAND ATPase/NTPase defense-system family. - reference: DOI:10.1126/science.abm4096 snippet: Avs1 to Avs3 recognize the large terminase subunit, and Avs4 recognizes the portal notes: Gao et al. support Avs4 as a phage-portal-sensing member of the AVAST receptor family. - reference: DOI:10.1126/science.abm4096 snippet: In all four cases, target recognition led to Avs protein activation and antiviral activity notes: Gao et al. connect Avs1 through Avs4 target recognition to Avs activation and antiviral activity. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: '| Avs | 10\.1126/science\.aba0372 | Diverse enzymatic activities mediate antiviral immunity in prokaryotes | ' notes: The pinned DefenseFinder article registry maps the Avs source key to the Gao et al. pangenome-scale antiviral-immunity paper. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md snippet: '| Avs_IV__Avs4A | Avs_IV__Avs4A | Avs_IV | Custom | 60 |' notes: The pinned DefenseFinder HMM inventory records Avs_IV__Avs4A under the Avs_IV model namespace. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv snippet: "Avs\tAvs_IV\t1\t1\tAvs_IV__Avs4A\t\t\t" notes: The pinned DefenseFinder rules table models Avs_IV as an Avs subsystem with an Avs4A profile. causal_graphs: - graph_id: avs_iv_locus_phage_portal_recognition title: Avs IV loci support phage portal recognition description: Conservative system-level sketch linking an Avs_IV locus to Avs4-mediated phage portal recognition and Avs IV system possession. scope_status: NONMECHANISTIC scope_notes: The graph captures Avs_IV at locus and Avs4 phage-portal recognition level without asserting the exact Avs4A component role, direct effector activity, native host breadth, sensitive-phage breadth, or whether every DefenseFinder Avs_IV prediction is a complete experimentally active Avs IV locus. nodes: - node_id: avs_iv_locus label: Avs IV locus node_type: GENETIC_ELEMENT description: An AVAST subtype IV locus represented in DefenseFinder by an Avs4A profile. - node_id: avs4_phage_portal_recognition label: Avs4 phage portal recognition node_type: BIOLOGICAL_PROCESS description: Recognition of an infecting phage portal protein by an Avs4 antiviral STAND-family receptor. - node_id: avs_iv_system_trait label: Avs IV system node_type: TRAIT grounding: traitmech:000537 description: Possession of a genome-encoded Avs IV phage-defense system. - node_id: avast_system_trait label: AVAST system node_type: TRAIT grounding: traitmech:000239 description: Possession of a genome-encoded AVAST phage-defense system. edges: - subject: avs_iv_locus predicate: contributes to predicate_id: RO:0002326 object: avs4_phage_portal_recognition description: Avs IV loci encode Avs4 components, and Avs4 belongs to the AVAST receptors that recognize the phage portal protein. evidence: - reference: DOI:10.1126/science.abm4096 snippet: Avs1 to Avs3 recognize the large terminase subunit, and Avs4 recognizes the portal notes: Gao et al. support Avs4 as a phage-portal-sensing member of the AVAST receptor family. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md snippet: '| Avs_IV__Avs4A | Avs_IV__Avs4A | Avs_IV | Custom | 60 |' notes: The pinned DefenseFinder HMM inventory records Avs_IV__Avs4A under the Avs_IV model namespace. - subject: avs4_phage_portal_recognition predicate: confers predicate_id: METPO:2007700 object: avs_iv_system_trait description: The first-pass Avs IV system trait is realized by Avs4 target recognition and downstream antiviral activity. evidence: - reference: DOI:10.1126/science.abm4096 snippet: Avs1 to Avs3 recognize the large terminase subunit, and Avs4 recognizes the portal notes: Gao et al. support Avs4 as a phage-portal-sensing member of the AVAST receptor family. - reference: DOI:10.1126/science.abm4096 snippet: In all four cases, target recognition led to Avs protein activation and antiviral activity notes: Gao et al. connect Avs1 through Avs4 target recognition to Avs activation and antiviral activity. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv snippet: "Avs\tAvs_IV\t1\t1\tAvs_IV__Avs4A\t\t\t" notes: The pinned DefenseFinder rules table models Avs_IV as an Avs subsystem with an Avs4A profile. - subject: avs_iv_system_trait predicate: is a predicate_id: rdfs:subClassOf object: avast_system_trait description: Avs IV system possession is an AVAST-system trait. evidence: - reference: DOI:10.1126/science.aba0372 snippet: AVAST, antiviral ATPase/NTPase of the STAND superfamily notes: Gao et al. coined AVAST as an antiviral STAND ATPase/NTPase defense-system family. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: '| Avs | 10\.1126/science\.aba0372 | Diverse enzymatic activities mediate antiviral immunity in prokaryotes | ' notes: The pinned DefenseFinder article registry maps the Avs source key to the Gao et al. pangenome-scale antiviral-immunity paper. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv snippet: "Avs\tAvs_IV\t1\t1\tAvs_IV__Avs4A\t\t\t" notes: The pinned DefenseFinder rules table models Avs_IV as an Avs subsystem with an Avs4A profile. discussions: - discussion_id: avs-iv-component-and-effector-gap prompt: Resolve the Avs4A component role, direct effector chemistry, exact phage-trigger mapping, native host breadth, and sensitive-phage breadth before minting Avs IV mechanism or component children. kind: KNOWLEDGE_GAP status: OPEN rationale: Gao et al. support Avs4 phage-portal recognition and Avs activation during antiviral defense, and the pinned DefenseFinder HMM inventory and rules table support Avs_IV as a subtype IV model with an Avs4A profile. This first-pass record leaves the exact component role, downstream effector chemistry, native host breadth, sensitive-phage breadth, and profile-to-activity requirements unresolved. evidence: - reference: DOI:10.1126/science.abm4096 snippet: Avs1 to Avs3 recognize the large terminase subunit, and Avs4 recognizes the portal notes: Gao et al. support Avs4 as a phage-portal-sensing member of the AVAST receptor family. - reference: DOI:10.1126/science.abm4096 snippet: In all four cases, target recognition led to Avs protein activation and antiviral activity notes: Gao et al. connect Avs1 through Avs4 target recognition to Avs activation and antiviral activity. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md snippet: '| Avs_IV__Avs4A | Avs_IV__Avs4A | Avs_IV | Custom | 60 |' notes: The pinned DefenseFinder HMM inventory records Avs_IV__Avs4A under the Avs_IV model namespace. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv snippet: "Avs\tAvs_IV\t1\t1\tAvs_IV__Avs4A\t\t\t" notes: The pinned DefenseFinder rules table models Avs_IV as an Avs subsystem with an Avs4A profile. attaches_to: - causal_graphs#avs_iv_locus_phage_portal_recognition posed_by: codex posed_date: '2026-10-02' curation_history: - timestamp: '2026-10-02T06:35:42Z' curator: codex action: MINTED_TRAITMECH_ID changes: Minted Avs IV system as a DOI- and DefenseFinder-backed GENOMICS TraitRecord under the AVAST system parent after an ignored-and-hidden duplicate review found no exact live TraitMech, METPO, history, or prior proposal record; the replacement placeholder is reserved in proposals/metpo_traitmech_v414. llm_assisted: true - timestamp: '2026-10-02T06:35:43Z' curator: codex action: REVIEW_CANONICAL_EXAMPLE_EVIDENCE_GAP changes: Reviewed Avs IV system during initial curation and left canonical_examples empty because Gao et al. and the pinned DefenseFinder tables support the Avs_IV model namespace and Avs4 phage-portal-recognition activity but not an accession-backed native microbial taxon exemplar with experimentally verified endogenous Avs IV activity. No paid research was used. llm_assisted: true