identifier: traitmech:000320 label: AbiC system definition: An abortive infection system in which an organism possesses an abiC-family locus represented by the DefenseFinder AbiC__AbiC profile and exemplified by the Lactococcus lactis subsp. lactis ME2 pTN20 determinant whose abiC structural gene confers Prf abortive resistance to small isometric-headed phage p2, reducing plaquing, plaque size, and burst size while killing most infected Prf-positive cells. definition_source: DOI:10.1128/jb.174.22.7463-7469.1992 trait_category: GENOMICS term_kind: CLASS mapping_status: PROPOSED parent_traits: - traitmech:000214 synonyms: - synonym_text: AbiC synonym_type: RELATED_SYNONYM source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md evidence: - reference: PMID:1429469 snippet: The genetic determinant for Prf (phage resistance five) was subcloned from the conjugative plasmid pTN20 notes: Durmaz et al. subcloned the Prf determinant from the Lactococcus lactis ME2 conjugative plasmid pTN20. - reference: PMID:1429469 snippet: Prf reduces the efficiency of plaquing to 10(-2) to 10(-3) and decreases the plaque size and burst size of the small isometric-headed phage p2 notes: Durmaz et al. measured Prf-dependent reductions in p2 phage plating efficiency, plaque size, and burst size. - reference: PMID:1429469 snippet: Prf does not prevent phage adsorption or promote restriction and modification activities notes: Durmaz et al. distinguished Prf activity from adsorption blocking and restriction-modification activities. - reference: PMID:1429469 snippet: 90% of Prf+ cells infected with phage p2 die. Thus, phage infections in Prf+ cells are aborted. notes: Durmaz et al. showed that most Prf-positive cells infected with phage p2 die and interpreted those p2 infections as aborted. - reference: PMID:1429469 snippet: DNA sequencing identified a 1,056-nucleotide structural gene designated abiC notes: Durmaz et al. identified the abiC structural gene in the Prf determinant. - reference: PMID:1429469 snippet: Prf+ expression was obtained when abiC was subcloned into the lactococcal expression vector pMG36e notes: Durmaz et al. showed that abiC expression is sufficient for Prf-positive activity in the pMG36e expression vector. - reference: PMID:1429469 snippet: Unlike abiA, the action of abiC does not appear to affect DNA replication notes: Durmaz et al. left AbiC downstream mechanism unresolved but distinguished it from AbiA-associated DNA-replication effects. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: 'AbiC | 10\.1016/j\.mib\.2005\.06\.006 | Phage abortive infection in lactococci: variations on a theme' notes: The DefenseFinder article registry maps the named AbiC model namespace to a lactococcal abortive-infection review. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv snippet: "AbiC\tAbiC\t1\t1\tAbiC__AbiC" notes: The DefenseFinder rules table models AbiC as a one-component system requiring the AbiC__AbiC profile. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md snippet: '| AbiC__AbiC | AbiC__AbiC | AbiC | Custom | 20 |' notes: The DefenseFinder HMM inventory records AbiC__AbiC under the AbiC model namespace. canonical_examples: - taxon_id: NCBITaxon:1358 taxon_label: Lactococcus lactis note: Durmaz et al. subcloned the Prf determinant from the Lactococcus lactis subsp. lactis ME2 conjugative plasmid pTN20 and showed that the abiC structural gene confers Prf-positive abortive resistance against small isometric-headed phage p2. reference: DOI:10.1128/jb.174.22.7463-7469.1992 causal_graphs: - graph_id: abic_locus_aborts_lactococcal_phage_p2_infection title: AbiC Prf activity aborts lactococcal phage p2 infection description: Conservative system-level sketch linking an abiC-family locus to Prf abortive-infection activity, reduced p2 phage propagation, Prf-positive infected-cell death, and AbiC-system possession without asserting an unresolved molecular target. scope_status: NONMECHANISTIC scope_notes: The graph captures AbiC as a named DefenseFinder single-profile abortive-infection system whose ME2 pTN20 prototype restricts small isometric-headed phage p2. It leaves the direct phage trigger, AbiC molecular function, cell-death route, natural locus breadth, and phage escape routes unresolved. nodes: - node_id: abic_locus label: abiC locus node_type: GENETIC_ELEMENT description: An abiC-family abortive-infection locus represented by the DefenseFinder AbiC__AbiC profile. - node_id: abic_prf_activity label: AbiC Prf activity node_type: BIOLOGICAL_PROCESS description: Prf abortive-infection phage resistance mediated by the abiC structural gene. - node_id: p2_phage_propagation_reduction label: p2 phage propagation reduction node_type: BIOLOGICAL_PROCESS description: Reduced small isometric-headed phage p2 plating, plaque size, and burst size in an AbiC-containing Lactococcus lactis host. - node_id: prf_positive_infected_cell_death label: Prf-positive infected cell death node_type: BIOLOGICAL_PROCESS description: Death of most Prf-positive Lactococcus lactis cells after infection with phage p2. - node_id: abic_system_trait label: AbiC system node_type: TRAIT grounding: traitmech:000320 description: Possession of a genome-encoded AbiC abortive-infection phage-defense system. - node_id: abortive_infection_system_trait label: abortive infection system node_type: TRAIT grounding: traitmech:000214 description: Possession of a genome-encoded abortive-infection phage-defense system. edges: - subject: abic_locus predicate: contributes to predicate_id: RO:0002326 object: abic_prf_activity description: The abiC-family locus encodes the Prf abortive-infection phage-resistance determinant, and DefenseFinder models AbiC as a one-profile system. evidence: - reference: PMID:1429469 snippet: DNA sequencing identified a 1,056-nucleotide structural gene designated abiC notes: Durmaz et al. identified the abiC structural gene within the Prf determinant. - reference: PMID:1429469 snippet: Prf+ expression was obtained when abiC was subcloned into the lactococcal expression vector pMG36e notes: Durmaz et al. showed that abiC subcloning is sufficient for Prf-positive expression. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv snippet: "AbiC\tAbiC\t1\t1\tAbiC__AbiC" notes: The DefenseFinder rules table models AbiC as a one-component system requiring the AbiC__AbiC profile. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md snippet: '| AbiC__AbiC | AbiC__AbiC | AbiC | Custom | 20 |' notes: The DefenseFinder HMM inventory records AbiC__AbiC under the AbiC model namespace. - subject: abic_prf_activity predicate: contributes to predicate_id: RO:0002326 object: p2_phage_propagation_reduction description: AbiC Prf activity reduces phage p2 plating, plaque size, and burst size. evidence: - reference: PMID:1429469 snippet: Prf reduces the efficiency of plaquing to 10(-2) to 10(-3) and decreases the plaque size and burst size of the small isometric-headed phage p2 notes: Durmaz et al. measured reduced p2 plating efficiency, plaque size, and burst size in Prf-positive cells. - subject: abic_prf_activity predicate: contributes to predicate_id: RO:0002326 object: prf_positive_infected_cell_death description: AbiC Prf-positive activity is associated with death of most phage p2-infected host cells. evidence: - reference: PMID:1429469 snippet: 90% of Prf+ cells infected with phage p2 die. Thus, phage infections in Prf+ cells are aborted. notes: Durmaz et al. connect the Prf-positive phenotype to infected-cell death and aborted p2 infection. - subject: p2_phage_propagation_reduction predicate: confers predicate_id: METPO:2007700 object: abic_system_trait description: Reduced p2 phage propagation realizes the AbiC abortive-infection trait. evidence: - reference: PMID:1429469 snippet: Prf reduces the efficiency of plaquing to 10(-2) to 10(-3) and decreases the plaque size and burst size of the small isometric-headed phage p2 notes: Durmaz et al. measured reduced p2 plating efficiency, plaque size, and burst size in Prf-positive cells. - reference: PMID:1429469 snippet: Thus, abiC represents a second abortive system found in ME2 that acts at a different point of the phage lytic cycle. notes: Durmaz et al. place abiC in the abortive-infection class and distinguish it from the AbiA system. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: 'AbiC | 10\.1016/j\.mib\.2005\.06\.006 | Phage abortive infection in lactococci: variations on a theme' notes: The DefenseFinder article registry maps the named AbiC model namespace to a lactococcal abortive-infection review. - subject: abic_system_trait predicate: is a predicate_id: rdfs:subClassOf object: abortive_infection_system_trait description: AbiC system possession is an abortive-infection-system trait. evidence: - reference: PMID:1429469 snippet: Thus, abiC represents a second abortive system found in ME2 notes: Durmaz et al. place abiC in the abortive-infection class of phage defense. discussions: - discussion_id: abic-trigger-and-death-route-gap prompt: Resolve the AbiC phage trigger, AbiC molecular function, and infected-cell death route before minting narrower AbiC mechanism children. kind: KNOWLEDGE_GAP status: OPEN rationale: Durmaz et al. support AbiC as a named lactococcal abortive-infection determinant that reduces p2 plating, plaque size, and burst size while killing most Prf-positive infected cells. DefenseFinder represents AbiC with a one-profile rule, but this first system-level record leaves the phage trigger, AbiC molecular function, cell-death route, natural locus breadth, and phage escape routes unresolved. attaches_to: - causal_graphs#abic_locus_aborts_lactococcal_phage_p2_infection posed_by: codex posed_date: '2026-09-20' curation_history: - timestamp: '2026-09-20T22:01:24Z' curator: codex action: MINTED_TRAITMECH_ID changes: Minted AbiC system as a DOI-backed GENOMICS TraitRecord under the abortive infection 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_v197. llm_assisted: true