identifier: traitmech:000230 label: AbiT system definition: An abortive infection system in which an organism possesses the two-gene pED1 abiT locus whose constitutively cotranscribed abiTi and abiTii genes encode an AbiTi-AbiTii phage-resistance module that acts late in the 936/P335 lactococcal phage lytic cycle. definition_source: DOI:10.1128/JB.184.22.6325-6332.2002 trait_category: GENOMICS term_kind: CLASS mapping_status: PROPOSED parent_traits: - traitmech:000214 evidence: - reference: DOI:10.1128/JB.184.22.6325-6332.2002 snippet: Here, we describe the isolation and characterization of a novel Abi mechanism encoded by plasmid pED1 from L. lactis notes: Bouchard et al. identified the plasmid pED1-encoded AbiT abortive-infection mechanism in Lactococcus lactis. - reference: DOI:10.1128/JB.184.22.6325-6332.2002 snippet: The system is composed of two constitutively cotranscribed genes encoding putative proteins of 127 and 213 amino acids, named AbiTi and AbiTii, respectively notes: Bouchard et al. support defining AbiT around the paired abiTi and abiTii host genes rather than around a single gene. - reference: DOI:10.1128/JB.184.22.6325-6332.2002 snippet: The fact that resistant cells do not survive phage infection proves that the antiphage system carried by pED1 is an Abi mechanism. It was therefore named AbiT. notes: Bouchard et al. placed the pED1 phage-resistance determinant in the abortive-infection class and named it AbiT. - reference: DOI:10.1128/JB.184.22.6325-6332.2002 snippet: Two genes are responsible for the antiphage activity of AbiT notes: Bouchard et al. support a two-gene genetic basis for AbiT phage resistance. - reference: DOI:10.1128/JB.184.22.6325-6332.2002 snippet: It appears that AbiT affects DNA replication and also prevents effective encapsidation notes: Bouchard et al. connect AbiT to both impaired phage DNA replication and ineffective phage encapsidation. - reference: DOI:10.1128/AEM.01755-12 snippet: AbiT-resistant phage mutants derived from the wild-type AbiT-sensitive lactococcal phages p2, bIL170, and P008 were isolated and characterized notes: Labrie et al. generated AbiT-resistant mutants from three sensitive 936-group Lactococcus phages. - reference: DOI:10.1128/AEM.01755-12 snippet: three distinct phage genes involved in AbiT activity were identified notes: Labrie et al. found that AbiT sensitivity maps to multiple nonhomologous phage genes rather than one universal phage escape determinant. - reference: DOI:10.1128/AEM.01755-12 snippet: AbiT blocks capsid protein synthesis of the wild-type phage, while it does not affect the resistant phage p2.t3, mutated in the capsid gene notes: Labrie et al. connect a p2 major-capsid-protein escape mutation to restoration of capsid protein synthesis in the presence of AbiT. canonical_examples: - taxon_id: NCBITaxon:1358 taxon_label: Lactococcus lactis note: Bouchard et al. isolated pED1 from Lactococcus lactis W51, localized the AbiT phage-resistance phenotype to abiTi and abiTii, and showed that the determinant restricts 936 and P335 Lactococcus phages after transfer into phage-sensitive Lactococcus lactis strains. reference: DOI:10.1128/JB.184.22.6325-6332.2002 causal_graphs: - graph_id: abit_late_phage_development_block title: AbiT activity blocks late phage development description: Evidence-backed process sketch linking the two-gene abiT locus to AbiTi-AbiTii antiphage activity, impaired phage DNA replication or capsid production, restricted phage propagation, and abortive-infection system possession. scope_status: NONMECHANISTIC scope_notes: The graph captures AbiT at the system level without asserting a molecular function for AbiTi or AbiTii, the exact host target, the direct phage activator, or that every AbiT-insensitive phage mutates the same phage gene. nodes: - node_id: abit_locus label: abiT locus node_type: GENETIC_ELEMENT description: A two-gene abortive-infection locus encoding AbiTi and AbiTii. - node_id: abiti_abitii_antiphage_activity label: AbiTi-AbiTii antiphage activity node_type: BIOLOGICAL_PROCESS description: Abortive-infection antiphage activity mediated by the AbiTi and AbiTii host proteins. - node_id: interrupted_late_phage_development label: interrupted late phage development node_type: BIOLOGICAL_PROCESS description: AbiT-associated impairment of phage DNA replication, phage DNA encapsidation, or capsid protein synthesis after early phage gene expression. - node_id: restricted_phage_propagation label: restricted phage propagation node_type: BIOLOGICAL_PROCESS description: Reduced completion of 936 or P335 phage propagation in an AbiT-containing infected host cell. - node_id: abit_system_trait label: AbiT system node_type: TRAIT grounding: traitmech:000230 description: Possession of a genome-encoded AbiT two-component abortive-infection 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: abit_locus predicate: contributes to predicate_id: RO:0002326 object: abiti_abitii_antiphage_activity description: The abiT locus carries abiTi, abiTii, and the promoter required for the complete phage-resistance phenotype. evidence: - reference: DOI:10.1128/JB.184.22.6325-6332.2002 snippet: Two genes are responsible for the antiphage activity of AbiT notes: Bouchard et al. showed that both abiT genes are required for full AbiT activity. - subject: abiti_abitii_antiphage_activity predicate: contributes to predicate_id: RO:0002326 object: interrupted_late_phage_development description: AbiT activity interferes with late phage development after early phage gene expression. evidence: - reference: DOI:10.1128/JB.184.22.6325-6332.2002 snippet: It appears that AbiT affects DNA replication and also prevents effective encapsidation notes: Bouchard et al. found reduced DNA replication and failed encapsidation in AbiT-containing infected cells. - reference: DOI:10.1128/AEM.01755-12 snippet: AbiT blocks capsid protein synthesis of the wild-type phage, while it does not affect the resistant phage p2.t3, mutated in the capsid gene notes: Labrie et al. refine the AbiT phenotype by linking wild-type p2 capsid protein synthesis blockage to an AbiT-sensitive capsid gene. - subject: interrupted_late_phage_development predicate: contributes to predicate_id: RO:0002326 object: restricted_phage_propagation description: Failed phage DNA maturation or capsid production limits completion of the phage lytic cycle. evidence: - reference: DOI:10.1128/JB.184.22.6325-6332.2002 snippet: The monitoring of the intracellular phage infection process by DNA replication, gene expression, and electron microscopy as well as the study of phage mutants by genome mapping indicated that AbiT is likely to act at a later stage of the phage lytic cycle notes: Bouchard et al. support a late-stage block in the phage lytic cycle. - subject: restricted_phage_propagation predicate: confers predicate_id: METPO:2007700 object: abit_system_trait description: Restriction of 936/P335 phage propagation realizes the AbiT abortive-infection defense trait. evidence: - reference: DOI:10.1128/JB.184.22.6325-6332.2002 snippet: The fact that resistant cells do not survive phage infection proves that the antiphage system carried by pED1 is an Abi mechanism. It was therefore named AbiT. notes: Bouchard et al. define AbiT as a pED1 abortive-infection phage resistance system. - subject: abit_system_trait predicate: is a predicate_id: rdfs:subClassOf object: abortive_infection_system_trait description: AbiT system possession is an abortive-infection-system trait. evidence: - reference: DOI:10.1128/JB.184.22.6325-6332.2002 snippet: Here, we describe the isolation and characterization of a novel Abi mechanism encoded by plasmid pED1 from L. lactis notes: Bouchard et al. place AbiT in the abortive infection class of phage defense. curation_history: - timestamp: '2026-09-15T22:05:00Z' curator: codex action: MINTED_TRAITMECH_ID changes: Minted AbiT 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, or prior proposal record; the replacement placeholder is reserved in proposals/metpo_traitmech_v107. llm_assisted: true