identifier: traitmech:000374 label: Rst_DUF4238 system definition: A phage defense system in which an organism possesses a single-gene Rst_DUF4238 locus represented by DefenseFinder as an Rst_DUF4238__DUF4238_Pers single-profile model and experimentally linked to strong resistance against phage T7. definition_source: DOI:10.1016/j.chom.2022.02.018 trait_category: GENOMICS term_kind: CLASS mapping_status: PROPOSED parent_traits: - traitmech:000209 synonyms: - synonym_text: Rst_DUF4238 synonym_type: RELATED_SYNONYM source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md - synonym_text: Rst_DUF4238__DUF4238_Pers synonym_type: RELATED_SYNONYM source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md - synonym_text: DUF4238_Pers synonym_type: RELATED_SYNONYM source: https://gitlab.pasteur.fr/mdm-lab/wiki/-/raw/ee7647d8/content/3.defense-systems/rst_duf4238.md evidence: - reference: DOI:10.1016/j.chom.2022.02.018 snippet: The first system consists of a single protein with a DUF4238 domain (whose molecular function is currently unknown) that provides strong resistance against T7. notes: Rousset et al. describe the one-protein DUF4238 candidate from the P2-encoded hotspot and connect it to strong T7 resistance. - reference: DOI:10.1016/j.chom.2022.02.018 snippet: Phage resistance heatmaps of the validated defense systems show the median fold resistance of three independent replicates against a panel of eight phages notes: The Figure 5 legend frames the cloned P2-hotspot hits, including the DUF4238 system, as validated defense systems in a replicated phage-resistance heatmap. - reference: https://gitlab.pasteur.fr/mdm-lab/wiki/-/raw/ee7647d8/content/3.defense-systems/rst_duf4238.md snippet: Rst_DUF4238 is a single gene system found in a screen of phage and phage-satellites antiviral hotspots :ref{doi=10.1016/j.chom.2022.02.018}. It was shown to provide *E.coli* with a strong resistance against phage T7. notes: The pinned DefenseFinder wiki page names Rst_DUF4238 as a single-gene system and links it to strong T7 resistance. - reference: https://gitlab.pasteur.fr/mdm-lab/wiki/-/raw/ee7647d8/content/3.defense-systems/rst_duf4238.md snippet: As far as we are aware, the molecular mechanism is unknown. notes: The pinned DefenseFinder wiki page leaves the Rst_DUF4238 molecular mechanism unresolved. - reference: https://gitlab.pasteur.fr/mdm-lab/wiki/-/raw/ee7647d8/content/3.defense-systems/rst_duf4238.md snippet: 'The Rst_DUF4238 is composed of 1 protein: DUF4238.' notes: The pinned DefenseFinder wiki page describes Rst_DUF4238 as a one-component DUF4238 system. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: Rst_DUF4238 | 10\.1101/2021\.01\.21\.427644 | Prophage-encoded hotspots of bacterial immune systems notes: The DefenseFinder article registry maps the named Rst_DUF4238 system to the Rousset et al. preprint. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv snippet: "Rst_DUF4238\tRst_DUF4238\t1\t1\tRst_DUF4238__DUF4238_Pers\t\t\t" notes: The DefenseFinder rules table models Rst_DUF4238 as a single-profile system requiring Rst_DUF4238__DUF4238_Pers. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md snippet: '| Rst_DUF4238__DUF4238_Pers | Rst_DUF4238__DUF4238_Pers | Rst_DUF4238 | Custom | 100 |' notes: The DefenseFinder HMM inventory records Rst_DUF4238__DUF4238_Pers under Rst_DUF4238. causal_graphs: - graph_id: rst_duf4238_locus_restricts_t7 title: Rst_DUF4238 loci restrict T7 phage description: Conservative system-level sketch linking the named Rst_DUF4238 single-gene locus model to strong T7 phage resistance. scope_status: NONMECHANISTIC scope_notes: The graph captures Rst_DUF4238 as a named DefenseFinder single-profile phage-defense system while leaving native host breadth, the molecular activity of the DUF4238 component, exact DUF4238_Pers profile grounding, and the mechanism of T7 restriction unresolved. nodes: - node_id: rst_duf4238_locus label: Rst_DUF4238 locus node_type: GENETIC_ELEMENT description: A single-gene DUF4238 phage-defense locus represented by the custom DefenseFinder Rst_DUF4238__DUF4238_Pers profile. - node_id: t7_phage_resistance label: T7 phage resistance node_type: BIOLOGICAL_PROCESS description: Strong resistance against phage T7 in a host expressing an Rst_DUF4238 locus. - node_id: rst_duf4238_system_trait label: Rst_DUF4238 system node_type: TRAIT grounding: traitmech:000374 description: Possession of a genome-encoded Rst_DUF4238 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: rst_duf4238_locus predicate: contributes to predicate_id: RO:0002326 object: t7_phage_resistance description: Rousset et al. linked a cloned one-protein DUF4238 locus to strong T7 resistance, and DefenseFinder models Rst_DUF4238 as a single-profile DUF4238_Pers system. evidence: - reference: DOI:10.1016/j.chom.2022.02.018 snippet: The first system consists of a single protein with a DUF4238 domain (whose molecular function is currently unknown) that provides strong resistance against T7. notes: Rousset et al. describe the one-protein DUF4238 candidate from the P2-encoded hotspot and connect it to strong T7 resistance. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv snippet: "Rst_DUF4238\tRst_DUF4238\t1\t1\tRst_DUF4238__DUF4238_Pers\t\t\t" notes: The DefenseFinder rules table models Rst_DUF4238 as a single-profile system requiring Rst_DUF4238__DUF4238_Pers. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md snippet: '| Rst_DUF4238__DUF4238_Pers | Rst_DUF4238__DUF4238_Pers | Rst_DUF4238 | Custom | 100 |' notes: The DefenseFinder HMM inventory records Rst_DUF4238__DUF4238_Pers under Rst_DUF4238. - subject: t7_phage_resistance predicate: confers predicate_id: METPO:2007700 object: rst_duf4238_system_trait description: Strong T7 resistance realizes the Rst_DUF4238 system trait. evidence: - reference: DOI:10.1016/j.chom.2022.02.018 snippet: The first system consists of a single protein with a DUF4238 domain (whose molecular function is currently unknown) that provides strong resistance against T7. notes: Rousset et al. describe the one-protein DUF4238 candidate from the P2-encoded hotspot and connect it to strong T7 resistance. - reference: https://gitlab.pasteur.fr/mdm-lab/wiki/-/raw/ee7647d8/content/3.defense-systems/rst_duf4238.md snippet: Rst_DUF4238 is a single gene system found in a screen of phage and phage-satellites antiviral hotspots :ref{doi=10.1016/j.chom.2022.02.018}. It was shown to provide *E.coli* with a strong resistance against phage T7. notes: The pinned DefenseFinder wiki page names Rst_DUF4238 as a single-gene system and links it to strong T7 resistance. - subject: rst_duf4238_system_trait predicate: is a predicate_id: rdfs:subClassOf object: phage_defense_system description: Rst_DUF4238 system possession is a phage-defense-system trait. evidence: - reference: DOI:10.1016/j.chom.2022.02.018 snippet: Phage resistance heatmaps of the validated defense systems show the median fold resistance of three independent replicates against a panel of eight phages notes: The Figure 5 legend frames the cloned P2-hotspot hits, including the DUF4238 system, as validated defense systems in a replicated phage-resistance heatmap. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: Rst_DUF4238 | 10\.1101/2021\.01\.21\.427644 | Prophage-encoded hotspots of bacterial immune systems notes: The DefenseFinder article registry maps the named Rst_DUF4238 system to the Rousset et al. preprint. discussions: - discussion_id: rst-duf4238-host-mechanism-gap prompt: Resolve Rst_DUF4238 native host breadth, accession-level DUF4238 proteins, and the molecular mechanism of T7 restriction before minting narrower Rst_DUF4238 mechanism children. kind: KNOWLEDGE_GAP status: OPEN rationale: Rousset et al. support a one-protein DUF4238 P2-hotspot system that provides strong T7 resistance when expressed in Escherichia coli, and DefenseFinder represents Rst_DUF4238 as a single-profile Rst_DUF4238__DUF4238_Pers model. This first system-level record leaves native host breadth, accession-level component grounding, the profile-to-activity mapping, and the T7 restriction mechanism unresolved. evidence: - reference: DOI:10.1016/j.chom.2022.02.018 snippet: The first system consists of a single protein with a DUF4238 domain (whose molecular function is currently unknown) that provides strong resistance against T7. notes: Rousset et al. describe the one-protein DUF4238 candidate from the P2-encoded hotspot and connect it to strong T7 resistance. - reference: https://gitlab.pasteur.fr/mdm-lab/wiki/-/raw/ee7647d8/content/3.defense-systems/rst_duf4238.md snippet: As far as we are aware, the molecular mechanism is unknown. notes: The pinned DefenseFinder wiki page leaves the Rst_DUF4238 molecular mechanism unresolved. - reference: https://gitlab.pasteur.fr/mdm-lab/wiki/-/raw/ee7647d8/content/3.defense-systems/rst_duf4238.md snippet: 'The Rst_DUF4238 is composed of 1 protein: DUF4238.' notes: The pinned DefenseFinder wiki page describes Rst_DUF4238 as a one-component DUF4238 system. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv snippet: "Rst_DUF4238\tRst_DUF4238\t1\t1\tRst_DUF4238__DUF4238_Pers\t\t\t" notes: The DefenseFinder rules table models Rst_DUF4238 as a single-profile system requiring Rst_DUF4238__DUF4238_Pers. attaches_to: - causal_graphs#rst_duf4238_locus_restricts_t7 posed_by: codex posed_date: '2026-09-26' curation_history: - timestamp: '2026-09-26T07:22:10Z' curator: codex action: MINTED_TRAITMECH_ID changes: Minted Rst_DUF4238 system as a DOI-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; the replacement placeholder is reserved in proposals/metpo_traitmech_v251. llm_assisted: true - timestamp: '2026-09-26T07:32:10Z' curator: codex action: REVIEW_CANONICAL_EXAMPLE_EVIDENCE_GAP changes: Reviewed Rst_DUF4238 during canonical-example issue 444 enforcement and left canonical_examples empty because the sources support a cloned P2-hotspot DUF4238 locus assayed in Escherichia coli and a DefenseFinder RefSeq model example, but not a direct native host exemplar with experimental Rst_DUF4238 activity. No paid research was used. llm_assisted: true