identifier: traitmech:000508 label: Ig-like Schlafen system definition: A phage defense system in which an organism possesses a genome-encoded prokaryotic Schlafen nuclease fused to an immunoglobulin-like sensor domain that recognizes T5-like phage tail assembly chaperones and activates Schlafen tRNase defense. definition_source: DOI:10.1038/s41564-026-02277-8 trait_category: GENOMICS term_kind: CLASS mapping_status: PROPOSED parent_traits: - traitmech:000209 synonyms: - synonym_text: Shlafen_Ig-like synonym_type: RELATED_SYNONYM source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md - synonym_text: pSlfn5 synonym_type: RELATED_SYNONYM source: DOI:10.1038/s41564-026-02277-8 evidence: - reference: DOI:10.1038/s41564-026-02277-8 snippet: prokaryotic Schlafen nucleases are widespread antiviral effectors that protect bacteria from bacteriophages and are fused to a diverse array of phage-sensing domains. notes: Perez Taboada et al. support bacterial prokaryotic Schlafen nucleases as antiviral effectors fused to phage-sensing domains. - reference: DOI:10.1038/s41564-026-02277-8 snippet: Schlafen nuclease is fused to a previously unknown immunoglobulin-like sensor domain and demonstrated that it recognizes tail assembly chaperones of T5-like phages. notes: Perez Taboada et al. support Ig-like domain fusion and T5-like tail assembly chaperone recognition by an Ig-like prokaryotic Schlafen system. - reference: DOI:10.1038/s41564-026-02277-8 snippet: We expressed seven Enterobacterales Schlafen systems in Escherichia coli, identifying two that confer defence against coliphages. notes: Perez Taboada et al. cloned candidate Enterobacterales Schlafen systems into E. coli and observed coliphage defense for two of them. - reference: DOI:10.1038/s41564-026-02277-8 snippet: Upon activation, the Schlafen nuclease cleaves both E. coli and phage-encoded tRNAs and restricts T5 phage by reducing its burst size. notes: Perez Taboada et al. connect activation of an Ig-like RorSlfn5 nuclease to bacterial and phage tRNA cleavage and T5 burst-size reduction. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: '| Shlafen_Ig-like | 10\.1038/s41564-026-02277-8 | Bacterial Schlafen proteins mediate phage defence | ' notes: The pinned DefenseFinder article registry maps the Shlafen_Ig-like source key to the Perez Taboada et al. Schlafen phage-defense paper. causal_graphs: - graph_id: ig_like_schlafen_trna_cleavage title: Ig-like Schlafen systems cleave tRNAs after phage sensing description: Conservative system-level sketch linking an Ig-like prokaryotic Schlafen locus to T5-like tail assembly chaperone sensing, Schlafen nuclease-dependent tRNA cleavage, and the Ig-like Schlafen phage-defense trait. scope_status: NONMECHANISTIC scope_notes: The graph captures the Ig-like prokaryotic Schlafen DefenseFinder article namespace at system level and deliberately defers a protein-resolved RorSlfn5 mechanism. Perez Taboada et al. support an Ig-like Schlafen nuclease system that recognizes T5-like phage tail assembly chaperones and cleaves bacterial and phage tRNAs, but exact profile boundaries, natural host exemplars, phage trigger breadth, and DefenseFinder HMM/rules profiles are unresolved. nodes: - node_id: ig_like_schlafen_locus label: Ig-like Schlafen locus node_type: GENETIC_ELEMENT description: A locus encoding a prokaryotic Schlafen nuclease fused to an Ig-like sensor domain. - node_id: t5_like_tail_chaperone_sensing label: T5-like tail chaperone sensing node_type: BIOLOGICAL_PROCESS description: Recognition of T5-like phage tail assembly chaperones by an Ig-like prokaryotic Schlafen sensor domain. - node_id: schlafen_trna_cleavage label: Schlafen tRNA cleavage node_type: BIOLOGICAL_PROCESS description: Cleavage of bacterial and phage tRNAs by an activated Schlafen nuclease. - node_id: ig_like_schlafen_system_trait label: Ig-like Schlafen system node_type: TRAIT grounding: traitmech:000508 description: Possession of a genome-encoded Ig-like prokaryotic Schlafen phage-defense system. - node_id: phage_defense_system_trait 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: ig_like_schlafen_locus predicate: contributes to predicate_id: RO:0002326 object: t5_like_tail_chaperone_sensing description: Ig-like Schlafen loci encode a Schlafen nuclease fused to an Ig-like sensor domain that recognizes T5-like phage tail assembly chaperones. evidence: - reference: DOI:10.1038/s41564-026-02277-8 snippet: Schlafen nuclease is fused to a previously unknown immunoglobulin-like sensor domain and demonstrated that it recognizes tail assembly chaperones of T5-like phages. notes: Perez Taboada et al. support Ig-like domain fusion and T5-like tail assembly chaperone recognition by an Ig-like prokaryotic Schlafen system. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: '| Shlafen_Ig-like | 10\.1038/s41564-026-02277-8 | Bacterial Schlafen proteins mediate phage defence | ' notes: The pinned DefenseFinder article registry maps the Shlafen_Ig-like source key to the Perez Taboada et al. Schlafen phage-defense paper. - subject: t5_like_tail_chaperone_sensing predicate: activates predicate_id: RO:0002213 object: schlafen_trna_cleavage description: Phage-triggered activation of the Ig-like Schlafen nuclease leads to bacterial and phage tRNA cleavage. evidence: - reference: DOI:10.1038/s41564-026-02277-8 snippet: Schlafen nuclease is fused to a previously unknown immunoglobulin-like sensor domain and demonstrated that it recognizes tail assembly chaperones of T5-like phages. notes: Perez Taboada et al. support Ig-like domain fusion and T5-like tail assembly chaperone recognition by an Ig-like prokaryotic Schlafen system. - reference: DOI:10.1038/s41564-026-02277-8 snippet: Upon activation, the Schlafen nuclease cleaves both E. coli and phage-encoded tRNAs and restricts T5 phage by reducing its burst size. notes: Perez Taboada et al. connect activation of an Ig-like RorSlfn5 nuclease to bacterial and phage tRNA cleavage and T5 burst-size reduction. - subject: schlafen_trna_cleavage predicate: confers predicate_id: METPO:2007700 object: ig_like_schlafen_system_trait description: Schlafen tRNase activity restricts T5 phage and realizes the organism-level Ig-like Schlafen system trait. evidence: - reference: DOI:10.1038/s41564-026-02277-8 snippet: prokaryotic Schlafen nucleases are widespread antiviral effectors that protect bacteria from bacteriophages and are fused to a diverse array of phage-sensing domains. notes: Perez Taboada et al. support bacterial prokaryotic Schlafen nucleases as antiviral effectors fused to phage-sensing domains. - reference: DOI:10.1038/s41564-026-02277-8 snippet: Upon activation, the Schlafen nuclease cleaves both E. coli and phage-encoded tRNAs and restricts T5 phage by reducing its burst size. notes: Perez Taboada et al. connect activation of an Ig-like RorSlfn5 nuclease to bacterial and phage tRNA cleavage and T5 burst-size reduction. - subject: ig_like_schlafen_system_trait predicate: is a predicate_id: rdfs:subClassOf object: phage_defense_system_trait description: Ig-like Schlafen system possession is a phage-defense-system trait. evidence: - reference: DOI:10.1038/s41564-026-02277-8 snippet: prokaryotic Schlafen nucleases are widespread antiviral effectors that protect bacteria from bacteriophages and are fused to a diverse array of phage-sensing domains. notes: Perez Taboada et al. support bacterial prokaryotic Schlafen nucleases as antiviral effectors fused to phage-sensing domains. - reference: DOI:10.1038/s41564-026-02277-8 snippet: We expressed seven Enterobacterales Schlafen systems in Escherichia coli, identifying two that confer defence against coliphages. notes: Perez Taboada et al. cloned candidate Enterobacterales Schlafen systems into E. coli and observed coliphage defense for two of them. discussions: - discussion_id: ig-like-schlafen-defensefinder-profile-gap prompt: Resolve exact pSlfn5 family boundaries, natural host exemplars, T5-like tail chaperone trigger breadth, and DefenseFinder HMM/rules coverage before minting narrower Ig-like Schlafen mechanism or component traits. kind: KNOWLEDGE_GAP status: OPEN rationale: Perez Taboada et al. support prokaryotic Schlafen nucleases as widespread antiviral effectors and experimentally characterize the Ig-like RorSlfn5 nuclease as a T5-like tail chaperone-triggered tRNase, and the pinned DefenseFinder article registry maps the Shlafen_Ig-like key to the same article. The pinned HMM inventory and rules table have no exact Schlafen rows. This first-pass record therefore does not resolve exact pSlfn5 family boundaries, natural host exemplars, accession-level Schlafen proteins, full phage trigger breadth, or a reusable DefenseFinder profile model. evidence: - reference: DOI:10.1038/s41564-026-02277-8 snippet: prokaryotic Schlafen nucleases are widespread antiviral effectors that protect bacteria from bacteriophages and are fused to a diverse array of phage-sensing domains. notes: Perez Taboada et al. support bacterial prokaryotic Schlafen nucleases as antiviral effectors fused to phage-sensing domains. - reference: DOI:10.1038/s41564-026-02277-8 snippet: Schlafen nuclease is fused to a previously unknown immunoglobulin-like sensor domain and demonstrated that it recognizes tail assembly chaperones of T5-like phages. notes: Perez Taboada et al. support Ig-like domain fusion and T5-like tail assembly chaperone recognition by an Ig-like prokaryotic Schlafen system. - reference: DOI:10.1038/s41564-026-02277-8 snippet: Upon activation, the Schlafen nuclease cleaves both E. coli and phage-encoded tRNAs and restricts T5 phage by reducing its burst size. notes: Perez Taboada et al. connect activation of an Ig-like RorSlfn5 nuclease to bacterial and phage tRNA cleavage and T5 burst-size reduction. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: '| Shlafen_Ig-like | 10\.1038/s41564-026-02277-8 | Bacterial Schlafen proteins mediate phage defence | ' notes: The pinned DefenseFinder article registry maps the Shlafen_Ig-like source key to the Perez Taboada et al. Schlafen phage-defense 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 Shlafen_Ig-like, Schlafen, or pSlfn5 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 Shlafen_Ig-like, Schlafen, or pSlfn5 system row. attaches_to: - causal_graphs#ig_like_schlafen_trna_cleavage posed_by: codex posed_date: '2026-10-01' curation_history: - timestamp: '2026-10-01T06:21:00Z' curator: codex action: MINTED_TRAITMECH_ID changes: Minted Ig-like Schlafen system as a DOI- and DefenseFinder-backed GENOMICS TraitRecord under the phage defense 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_v385. llm_assisted: true - timestamp: '2026-10-01T06:21:01Z' curator: codex action: REVIEW_CANONICAL_EXAMPLE_EVIDENCE_GAP changes: Reviewed Ig-like Schlafen system during initial curation and left canonical_examples empty because Perez Taboada et al. support RorSlfn5 from Raoultella ornithinolytica, but an NCBI Taxonomy lookup for that current name did not resolve during first-pass curation. No paid research was used. llm_assisted: true