identifier: traitmech:000364 label: PrrC system definition: A phage defense system in which an organism possesses a PrrC locus represented by DefenseFinder as a two-profile model requiring PrrC__EcoprrI and PrrC__PrrC, with type I restriction-modification components accepted as accessory markers. definition_source: DOI:10.1186/1743-422X-7-360 trait_category: GENOMICS term_kind: CLASS mapping_status: PROPOSED parent_traits: - traitmech:000209 synonyms: - synonym_text: PrrC synonym_type: RELATED_SYNONYM source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md - synonym_text: PrrC__EcoprrI synonym_type: RELATED_SYNONYM source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md - synonym_text: PrrC__PrrC synonym_type: RELATED_SYNONYM source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md evidence: - reference: PMID:21129205 snippet: phage exclusion systems that involve T4-mediated activation of a latent endoribonuclease (PrrC) and cofactor-assisted activation of EF-Tu proteolysis (Gol-Lit) notes: Uzan et al. name PrrC as a T4-mediated phage-exclusion system that activates a latent endoribonuclease. - reference: PMID:16790566 snippet: The tRNA(Lys) anticodon nuclease PrrC is associated in latent form with the type Ic DNA restriction endonuclease EcoprrI and activated by a phage T4-encoded inhibitor of EcoprrI. notes: Blanga-Kanfi et al. support latent PrrC association with the EcoprrI restriction endonuclease and activation by a T4-encoded EcoprrI inhibitor. - reference: PMID:16790566 snippet: This triad exists in all the known PrrC homologs but only some of them feature residues needed for tRNA(Lys) recognition by the Escherichia coli prototype. notes: Blanga-Kanfi et al. support a family of PrrC homologs whose substrate-recognition residues can differ from the Escherichia coli prototype. - reference: PMID:16790566 snippet: The differential conservation and consistent genetic linkage of the PrrC proteins with EcoprrI homologs portray them as a family of restriction RNases of diverse substrate specificities that are mobilized when an associated DNA restriction nuclease is compromised. notes: Blanga-Kanfi et al. support genetic linkage between PrrC proteins and EcoprrI homologs as a restriction-RNase family mobilized when an associated restriction nuclease is compromised. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: 'PrrC | 10\.1186/1743-422X-7-360 | Post-transcriptional control by bacteriophage T4: mRNA decay and inhibition of translation initiation' notes: The DefenseFinder article registry maps the named PrrC system to the Uzan et al. T4 post-transcriptional-control review. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv snippet: "PrrC\tPrrC\t2\t2\tPrrC__EcoprrI, PrrC__PrrC\tRM__Type_I_REases, RM__Type_I_S" notes: The DefenseFinder rules table models PrrC as a two-profile system requiring the PrrC__EcoprrI and PrrC__PrrC profiles, with type I restriction-modification components as accessory markers. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md snippet: '| PrrC__EcoprrI | PrrC__EcoprrI | PrrC | Custom | 20 |' notes: The DefenseFinder HMM inventory records PrrC__EcoprrI under PrrC. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md snippet: '| PrrC__PrrC | PrrC__PrrC | PrrC | Custom | 100 |' notes: The DefenseFinder HMM inventory records PrrC__PrrC under PrrC. causal_graphs: - graph_id: prrc_locus_restricts_t4_phage title: PrrC loci confer T4 phage exclusion description: Conservative system-level sketch linking possession of a PrrC locus to T4-induced PrrC restriction-RNase defense without asserting the exact T4 trigger, natural substrate, or accessory component logic. scope_status: NONMECHANISTIC scope_notes: The graph captures PrrC as a named DefenseFinder two-profile phage-exclusion system while leaving natural homolog substrate specificity, the exact EcoprrI accessory composition and profile matching, the phage trigger logic, and PrrC profile-to-activity mapping unresolved. nodes: - node_id: prrc_locus label: PrrC locus node_type: GENETIC_ELEMENT description: A DefenseFinder PrrC phage-defense locus represented by PrrC__EcoprrI and PrrC__PrrC profiles. - node_id: t4_induced_prrc_rnase_defense label: T4-induced PrrC RNase defense node_type: BIOLOGICAL_PROCESS description: Mobilization of a PrrC-family restriction RNase during bacteriophage T4 interference with the associated EcoprrI restriction nuclease. - node_id: prrc_system_trait label: PrrC system node_type: TRAIT grounding: traitmech:000364 description: Possession of a genome-encoded PrrC 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: prrc_locus predicate: contributes to predicate_id: RO:0002326 object: t4_induced_prrc_rnase_defense description: PrrC proteins are genetically linked with EcoprrI homologs and can be mobilized when associated DNA restriction nucleases are compromised, and DefenseFinder models PrrC as a two-profile system. evidence: - reference: PMID:21129205 snippet: phage exclusion systems that involve T4-mediated activation of a latent endoribonuclease (PrrC) and cofactor-assisted activation of EF-Tu proteolysis (Gol-Lit) notes: Uzan et al. identify PrrC as a latent endonuclease participating in T4-mediated phage exclusion. - reference: PMID:16790566 snippet: The tRNA(Lys) anticodon nuclease PrrC is associated in latent form with the type Ic DNA restriction endonuclease EcoprrI and activated by a phage T4-encoded inhibitor of EcoprrI. notes: Blanga-Kanfi et al. connect PrrC to EcoprrI and T4 inhibitor-triggered activation. - reference: PMID:16790566 snippet: The differential conservation and consistent genetic linkage of the PrrC proteins with EcoprrI homologs portray them as a family of restriction RNases of diverse substrate specificities that are mobilized when an associated DNA restriction nuclease is compromised. notes: Blanga-Kanfi et al. generalize PrrC homologs as EcoprrI-linked restriction RNases. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: 'PrrC | 10\.1186/1743-422X-7-360 | Post-transcriptional control by bacteriophage T4: mRNA decay and inhibition of translation initiation' notes: The DefenseFinder article registry maps the named PrrC system to the Uzan et al. T4 post-transcriptional-control review. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv snippet: "PrrC\tPrrC\t2\t2\tPrrC__EcoprrI, PrrC__PrrC\tRM__Type_I_REases, RM__Type_I_S" notes: The DefenseFinder rules table models PrrC as a two-profile system requiring the PrrC__EcoprrI and PrrC__PrrC profiles, with type I restriction-modification components as accessory markers. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md snippet: '| PrrC__EcoprrI | PrrC__EcoprrI | PrrC | Custom | 20 |' notes: The DefenseFinder HMM inventory records PrrC__EcoprrI under PrrC. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md snippet: '| PrrC__PrrC | PrrC__PrrC | PrrC | Custom | 100 |' notes: The DefenseFinder HMM inventory records PrrC__PrrC under PrrC. - subject: t4_induced_prrc_rnase_defense predicate: confers predicate_id: METPO:2007700 object: prrc_system_trait description: T4-induced PrrC RNase defense realizes the PrrC system trait. evidence: - reference: PMID:16790566 snippet: The tRNA(Lys) anticodon nuclease PrrC is associated in latent form with the type Ic DNA restriction endonuclease EcoprrI and activated by a phage T4-encoded inhibitor of EcoprrI. notes: Blanga-Kanfi et al. support latent PrrC activation by a T4-encoded inhibitor of EcoprrI. - reference: PMID:16790566 snippet: The differential conservation and consistent genetic linkage of the PrrC proteins with EcoprrI homologs portray them as a family of restriction RNases of diverse substrate specificities that are mobilized when an associated DNA restriction nuclease is compromised. notes: Blanga-Kanfi et al. support broader mobilization of EcoprrI-linked PrrC-family restriction RNases. - subject: prrc_system_trait predicate: is a predicate_id: rdfs:subClassOf object: phage_defense_system description: PrrC system possession is a phage-defense-system trait. evidence: - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: 'PrrC | 10\.1186/1743-422X-7-360 | Post-transcriptional control by bacteriophage T4: mRNA decay and inhibition of translation initiation' notes: The DefenseFinder article registry maps the named PrrC system to the Uzan et al. T4 post-transcriptional-control review. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv snippet: "PrrC\tPrrC\t2\t2\tPrrC__EcoprrI, PrrC__PrrC\tRM__Type_I_REases, RM__Type_I_S" notes: The DefenseFinder rules table models PrrC as a two-profile system requiring the PrrC__EcoprrI and PrrC__PrrC profiles, with type I restriction-modification components as accessory markers. discussions: - discussion_id: prrc-mechanism-gap prompt: Resolve natural PrrC homolog substrate specificity, exact EcoprrI accessory composition and profile matching, and phage trigger logic before minting narrower PrrC mechanism children. kind: KNOWLEDGE_GAP status: OPEN rationale: Uzan et al. summarize PrrC as a T4 phage-exclusion system, Blanga-Kanfi et al. support PrrC and EcoprrI homologs as genetically linked restriction RNases, and DefenseFinder models PrrC as a two-profile system with EcoprrI and PrrC markers plus type I restriction-modification accessories. The natural substrates, accessory composition, and phage trigger logic remain unresolved. attaches_to: - causal_graphs#prrc_locus_restricts_t4_phage posed_by: codex posed_date: '2026-09-22' curation_history: - timestamp: '2026-09-22T11:25:19Z' curator: codex action: MINTED_TRAITMECH_ID changes: Minted PrrC 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_v241. llm_assisted: true - timestamp: '2026-09-22T11:39:03Z' curator: codex action: REVIEW_CANONICAL_EXAMPLE_EVIDENCE_GAP changes: 'Reviewed the PrrC canonical_examples gap and left canonical_examples empty: the current evidence supports a named PrrC phage-exclusion system, the pinned DefenseFinder PrrC profiles, and EcoprrI-linked PrrC homologs, but does not cite a directly observed natural microbial taxon with a source-backed PrrC locus. No paid research was used. Fixes #1247.' llm_assisted: true - timestamp: '2026-09-22T11:42:52Z' curator: codex action: ADDRESS_PR_REVIEW changes: 'Resolved PR #1245 review issue #1249 by removing the bare EcoprrI component name from PrrC system related synonyms while retaining the DefenseFinder PrrC__EcoprrI profile name and Blanga-Kanfi evidence for EcoprrI-linked PrrC homologs.' llm_assisted: true