identifier: traitmech:000280 label: Dsr system definition: A phage defense system in which an organism possesses a defense-associated sirtuin locus whose SIR2-domain effector can deplete NAD+ during bacteriophage defense and is modeled by DefenseFinder as Dsr subtypes. definition_source: DOI:10.1038/s41564-022-01207-8 trait_category: GENOMICS term_kind: CLASS mapping_status: PROPOSED parent_traits: - traitmech:000209 synonyms: - synonym_text: Dsr synonym_type: EXACT_SYNONYM source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md - synonym_text: defense-associated sirtuin synonym_type: RELATED_SYNONYM source: DOI:10.1126/science.aba0372 evidence: - reference: DOI:10.1126/science.aba0372 snippet: we selected 48 candidate systems to test experimentally for defense activity notes: Gao et al. used heterologous reconstitution and phage challenge as their experimental screen for computationally predicted antiphage systems. - reference: DOI:10.1126/science.aba0372 snippet: dsr, defense-associated sirtuin notes: Gao et al. introduced dsr as a defense-associated sirtuin name in the candidate-system activity figure. - reference: DOI:10.1126/science.aba0372 snippet: Additional systems include proteins containing a SIR2 (sirtuin) deacetylase domain notes: Gao et al. place SIR2-domain proteins among additional antiphage defense-system candidates in their domain-architecture analysis. - reference: DOI:10.1038/s41564-022-01207-8 snippet: DSR proteins degrade nicotinamide adenine dinucleotide (NAD+) during infection, depleting the cell of this essential molecule and aborting phage propagation notes: Garb et al. showed that DSR SIR2-domain proteins can defend through infection-coupled NAD+ depletion. - reference: DOI:10.1038/s41564-022-01207-8 snippet: DSR2, directly identifies phage tail tube proteins and then becomes an active NADase in Bacillus subtilis notes: Garb et al. experimentally resolved the phage-derived activation cue for one Bacillus subtilis DSR2 system. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: Dsr | 10\.1126/science\.aba0372 | Diverse enzymatic activities mediate antiviral immunity in prokaryotes notes: The DefenseFinder article registry maps the named Dsr system to the Gao et al. antiphage-system discovery paper. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv snippet: "Dsr\tDsr_I\t1\t1\tDsr_I__Dsr1" notes: The DefenseFinder rules table models Dsr_I as a single-profile Dsr subtype. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md snippet: Dsr_I__Dsr1 | Dsr_I__Dsr1 | Dsr_I notes: The DefenseFinder HMM inventory records the Dsr1 profile in the Dsr_I model namespace. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv snippet: "Dsr\tDsr_II\t1\t1\tDsr_II__Dsr2" notes: The DefenseFinder rules table models Dsr_II as a single-profile Dsr subtype. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md snippet: Dsr_II__Dsr2 | Dsr_II__Dsr2 | Dsr_II notes: The DefenseFinder HMM inventory records the Dsr2 profile in the Dsr_II model namespace. causal_graphs: - graph_id: dsr_sirtuin_antiphage_defense title: Dsr loci encode SIR2-domain antiphage proteins description: Conservative system-level sketch linking a Dsr locus to SIR2-domain NAD+ depletion, subtype-specific bacteriophage resistance, and the Dsr system trait. scope_status: NONMECHANISTIC scope_notes: The graph captures Dsr systems at the family level while leaving DefenseFinder Dsr_I/Dsr_II profile boundaries, subtype-specific triggers outside DSR2, host ranges, anti-defense proteins, and exact phage targets unresolved. This Dsr family is distinct from metabolic dissimilatory sulfite reductase DsrAB systems. nodes: - node_id: dsr_locus label: Dsr locus node_type: GENETIC_ELEMENT description: A defense-associated sirtuin antiphage locus represented by Dsr subtype profiles. - node_id: sir2_domain_antiphage_activity label: SIR2-domain antiphage activity node_type: MOLECULAR_FUNCTION description: NADase-associated molecular activity carried by a Dsr SIR2-domain antiphage protein. - node_id: subtype_specific_phage_resistance label: subtype-specific phage resistance node_type: BIOLOGICAL_PROCESS description: Protection against particular bacteriophages by a Dsr subtype. - node_id: dsr_system_trait label: Dsr system node_type: TRAIT grounding: traitmech:000280 description: Possession of a genome-encoded defense-associated sirtuin 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: dsr_locus predicate: contributes to predicate_id: RO:0002326 object: sir2_domain_antiphage_activity description: Dsr loci encode SIR2-domain defense-associated sirtuin proteins. evidence: - reference: DOI:10.1126/science.aba0372 snippet: dsr, defense-associated sirtuin notes: Gao et al. connect the Dsr name to a defense-associated sirtuin candidate. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md snippet: Dsr_I__Dsr1 | Dsr_I__Dsr1 | Dsr_I notes: DefenseFinder includes Dsr1 in the Dsr_I custom model profile inventory. - subject: sir2_domain_antiphage_activity predicate: contributes to predicate_id: RO:0002326 object: subtype_specific_phage_resistance description: Garb et al. showed that DSR SIR2-domain effectors can degrade NAD+ during infection and abort phage propagation. evidence: - reference: DOI:10.1038/s41564-022-01207-8 snippet: DSR proteins degrade nicotinamide adenine dinucleotide (NAD+) during infection, depleting the cell of this essential molecule and aborting phage propagation notes: DSR SIR2-domain activity can deplete NAD+ during infection in an abortive phage defense outcome. - subject: dsr_locus predicate: contributes to predicate_id: RO:0002326 object: subtype_specific_phage_resistance description: Garb et al. support DSR NAD+ depletion as an abortive phage-defense outcome, while DefenseFinder models Dsr_I and Dsr_II as named Dsr subtypes. evidence: - reference: DOI:10.1038/s41564-022-01207-8 snippet: DSR proteins degrade nicotinamide adenine dinucleotide (NAD+) during infection, depleting the cell of this essential molecule and aborting phage propagation notes: Garb et al. directly support infection-coupled DSR NAD+ depletion as an abortive antiphage output. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv snippet: "Dsr\tDsr_I\t1\t1\tDsr_I__Dsr1" notes: The DefenseFinder rules table supports Dsr_I as a named defense-system subtype model with a Dsr1 profile. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv snippet: "Dsr\tDsr_II\t1\t1\tDsr_II__Dsr2" notes: The DefenseFinder rules table supports Dsr_II as a named defense-system subtype model with a Dsr2 profile. - subject: subtype_specific_phage_resistance predicate: confers predicate_id: METPO:2007700 object: dsr_system_trait description: DefenseFinder represents Dsr as Dsr_I and Dsr_II subtypes within its Dsr system models. evidence: - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv snippet: "Dsr\tDsr_I\t1\t1\tDsr_I__Dsr1" notes: The Dsr_I rule links the Dsr system namespace to the Dsr_I subtype and Dsr1 profile. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv snippet: "Dsr\tDsr_II\t1\t1\tDsr_II__Dsr2" notes: The Dsr_II rule links the Dsr system namespace to the Dsr_II subtype and Dsr2 profile. - subject: dsr_system_trait predicate: is a predicate_id: rdfs:subClassOf object: phage_defense_system description: Dsr system possession is a phage-defense-system trait. evidence: - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: Dsr | 10\.1126/science\.aba0372 | Diverse enzymatic activities mediate antiviral immunity in prokaryotes notes: DefenseFinder associates Dsr with the Gao et al. prokaryotic antiviral-immunity paper. discussions: - discussion_id: dsr-sirtuin-mechanism-gap prompt: Map DefenseFinder Dsr_I and Dsr_II profiles onto experimentally resolved DSR1 and DSR2 NADase triggers, host ranges, anti-defense proteins, and Dsr naming collisions before minting narrower Dsr mechanism children. kind: KNOWLEDGE_GAP status: OPEN rationale: Gao et al. support defense-associated sirtuin proteins as antiphage system components, Garb et al. resolved NAD+ depletion for multiple SIR2-dependent defense systems and tail tube-triggered NADase activation for B. subtilis DSR2, and DefenseFinder models Dsr_I and Dsr_II. This first record stays at Dsr-family level until the DefenseFinder subtype profiles can be aligned to specific experimental DSR1/DSR2 systems, trigger proteins, host ranges, and phage-encoded anti-DSR proteins. The DefenseFinder Dsr system is also lexically distinct from metabolic DsrAB dissimilatory sulfite reductase systems. attaches_to: - causal_graphs#dsr_sirtuin_antiphage_defense posed_by: codex posed_date: '2026-09-19' curation_history: - timestamp: '2026-09-19T13:00:46Z' curator: codex action: MINTED_TRAITMECH_ID changes: Minted Dsr system as a DOI-backed GENOMICS TraitRecord under phage defense system after an ignored-and-hidden duplicate review found no exact phage-defense Dsr TraitMech, METPO, or prior proposal record; the replacement placeholder is reserved in proposals/metpo_traitmech_v157. llm_assisted: true