identifier: traitmech:000516 label: Brc24 system definition: A phage defense system in which an organism possesses a gcu24/Brc24 bacteriophage-resistance integron cassette that supports growth during bacteriophage challenge. definition_source: DOI:10.1126/science.ads0915 trait_category: GENOMICS term_kind: CLASS mapping_status: PROPOSED parent_traits: - traitmech:000209 synonyms: - synonym_text: gcu24 synonym_type: RELATED_SYNONYM source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md - synonym_text: brc24 synonym_type: RELATED_SYNONYM source: DOI:10.1126/science.ads0915 evidence: - reference: DOI:10.1126/science.ads0915 snippet: Identification of gcu24 and gcu142 through double spot screening notes: Kieffer et al. report initial identification of gcu24 in a double-spot phage-resistance screen. - reference: DOI:10.1126/science.ads0915 snippet: gcu24 and gcu142, which show growth despite the presence of the phage, indicating successful identification and resistance. notes: Kieffer et al. support growth of the gcu24 clone during T4 phage challenge in the initial screen. - reference: DOI:10.1126/science.ads0915 snippet: defense profiles of identified Bacteriophage Resistance integron Cassettes (BRiCs) against a panel of different phages notes: Kieffer et al. classify positive integron cassettes as BRiCs and compare their defense profiles across a phage panel. - reference: DOI:10.1126/science.ads0915 snippet: 'C747 pMBA gcu24' notes: Kieffer et al.'s supplementary construct table lists the initial pMBA gcu24 screening plasmid. - reference: DOI:10.1126/science.ads0915 snippet: 'C806 pMBA brc24 E. coli IJ1862' notes: Kieffer et al.'s supplementary construct table lists pMBA brc24 in E. coli IJ1862 for high/low-MOI phage-panel testing. - reference: DOI:10.1126/science.ads0915 snippet: 'C816 pMBA brc24 K. pneumoniae' notes: Kieffer et al.'s supplementary construct table lists the pMBA brc24 plasmid introduced into Klebsiella pneumoniae KP5. - reference: DOI:10.1126/science.ads0915 snippet: 'C971 pBTZ PcW brc24' notes: Kieffer et al.'s supplementary construct table lists a Pseudomonas aeruginosa brc24 expression construct. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: '| gcu24 | 10\.1126/science\.ads0915 | Mobile integrons encode phage defense systems | ' notes: The pinned DefenseFinder article registry maps the gcu24 source key to the Kieffer et al. mobile-integron BRiC paper. causal_graphs: - graph_id: brc24_integron_cassette_confers_phage_resistance title: Brc24 BRiCs confer phage resistance description: Conservative system-level sketch linking a gcu24/Brc24 bacteriophage-resistance integron cassette to phage resistance and Brc24 system possession. scope_status: NONMECHANISTIC scope_notes: The graph captures Brc24 at the integron-cassette and phage-resistance-output level without asserting the native host range, exact sensitive-phage breadth outside the reported panels, direct molecular substrate, or a DefenseFinder HMM/rules profile absent from the pinned snapshot. nodes: - node_id: brc24_integron_cassette label: Brc24 integron cassette node_type: GENETIC_ELEMENT description: A mobile integron gene cassette recovered in the gcu24 screen and renamed as a Brc24 bacteriophage-resistance integron cassette. - node_id: brc24_phage_resistance label: Brc24 phage resistance node_type: BIOLOGICAL_PROCESS description: Reduced phage inhibition in cells carrying the gcu24/Brc24 integron cassette. - node_id: brc24_system_trait label: Brc24 system node_type: TRAIT grounding: traitmech:000516 description: Possession of a genome-encoded Brc24 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: brc24_integron_cassette predicate: contributes to predicate_id: RO:0002326 object: brc24_phage_resistance description: The gcu24/Brc24 integron cassette contributes to phage resistance during double-spot and phage-panel assays. evidence: - reference: DOI:10.1126/science.ads0915 snippet: Identification of gcu24 and gcu142 through double spot screening notes: Kieffer et al. report initial identification of gcu24 in a double-spot phage-resistance screen. - reference: DOI:10.1126/science.ads0915 snippet: 'C806 pMBA brc24 E. coli IJ1862' notes: Kieffer et al. cloned brc24 for E. coli IJ1862 phage-panel testing. - subject: brc24_phage_resistance predicate: confers predicate_id: METPO:2007700 object: brc24_system_trait description: Brc24-linked phage resistance realizes the Brc24 system possession trait. evidence: - reference: DOI:10.1126/science.ads0915 snippet: gcu24 and gcu142, which show growth despite the presence of the phage, indicating successful identification and resistance. notes: Kieffer et al. support growth of the gcu24 clone during T4 phage challenge in the initial screen. - reference: DOI:10.1126/science.ads0915 snippet: defense profiles of identified Bacteriophage Resistance integron Cassettes (BRiCs) against a panel of different phages notes: Kieffer et al. classify positive integron cassettes as BRiCs and compare their defense profiles across a phage panel. - subject: brc24_system_trait predicate: is a predicate_id: rdfs:subClassOf object: phage_defense_system description: Brc24 system possession is a phage-defense-system trait. evidence: - reference: DOI:10.1126/science.ads0915 snippet: defense profiles of identified Bacteriophage Resistance integron Cassettes (BRiCs) against a panel of different phages notes: Kieffer et al. classify positive integron cassettes as BRiCs and compare their defense profiles across a phage panel. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: '| gcu24 | 10\.1126/science\.ads0915 | Mobile integrons encode phage defense systems | ' notes: The pinned DefenseFinder article registry maps the gcu24 source key to the Kieffer et al. mobile-integron BRiC paper. discussions: - discussion_id: brc24-defensefinder-model-gap prompt: Resolve Brc24 native host breadth, exact sensitive-phage breadth, molecular output, and DefenseFinder HMM/rules coverage before minting narrower Brc24 mechanism children. kind: KNOWLEDGE_GAP status: OPEN rationale: Kieffer et al. identify gcu24/Brc24 as a bacteriophage-resistance integron cassette, and the pinned DefenseFinder article registry maps the gcu24 source key to the same Science article. The pinned HMM inventory and rules table have no exact gcu24 or Brc24 row, so the first-pass record leaves native-host breadth, profile boundaries, exact phage target breadth, and direct molecular output unresolved. evidence: - reference: DOI:10.1126/science.ads0915 snippet: Identification of gcu24 and gcu142 through double spot screening notes: Kieffer et al. report initial identification of gcu24 in a double-spot phage-resistance screen. - reference: DOI:10.1126/science.ads0915 snippet: defense profiles of identified Bacteriophage Resistance integron Cassettes (BRiCs) against a panel of different phages notes: Kieffer et al. classify positive integron cassettes as BRiCs and compare their defense profiles across a phage panel. - reference: DOI:10.1126/science.ads0915 snippet: 'C816 pMBA brc24 K. pneumoniae' notes: Kieffer et al. list brc24 in the heterologous Klebsiella pneumoniae KP5 BRiC panel. - reference: DOI:10.1126/science.ads0915 snippet: 'C971 pBTZ PcW brc24' notes: Kieffer et al. list brc24 in the heterologous Pseudomonas aeruginosa PAO1 BRiC panel. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: '| gcu24 | 10\.1126/science\.ads0915 | Mobile integrons encode phage defense systems | ' notes: The pinned DefenseFinder article registry maps the gcu24 source key to the Kieffer et al. mobile-integron BRiC paper. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md notes: A structured first-pass search of the pinned DefenseFinder HMM inventory found no exact gcu24, brc24, or Brc24 row. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv notes: A structured first-pass search of the pinned DefenseFinder rules table found no exact gcu24, brc24, or Brc24 system row. attaches_to: - causal_graphs#brc24_integron_cassette_confers_phage_resistance posed_by: codex posed_date: '2026-10-01' curation_history: - timestamp: '2026-10-01T13:34:00Z' curator: codex action: MINTED_TRAITMECH_ID changes: Minted Brc24 system as a DOI- and DefenseFinder-backed GENOMICS TraitRecord under phage defense system after an ignored-and-hidden duplicate review found no exact live TraitMech, METPO, history, or prior proposal record; kept the graph at BRiC integron-cassette level because the pinned DefenseFinder article registry names gcu24 but the pinned HMM inventory and rules table have no exact Brc24 row; the replacement placeholder is reserved in proposals/metpo_traitmech_v393. llm_assisted: true - timestamp: '2026-10-01T13:34:01Z' curator: codex action: REVIEW_CANONICAL_EXAMPLE_EVIDENCE_GAP changes: Reviewed Brc24 system during initial curation and left canonical_examples empty because the sources support heterologous gcu24/Brc24 phage-resistance assays and a DefenseFinder gcu24 article row, but not a direct named native microbial isolate exemplar with experimentally verified endogenous Brc24 activity. No paid research was used. llm_assisted: true