identifier: traitmech:000229 label: AbiK system definition: An abortive infection system in which an organism possesses an abiK locus encoding a reverse-transcriptase-related polymerase that uses conserved RT motifs for phage resistance and restricts 936/P335 lactococcal phage propagation. definition_source: DOI:10.1128/aem.63.4.1274-1283.1997 trait_category: GENOMICS term_kind: CLASS mapping_status: PROPOSED parent_traits: - traitmech:000214 evidence: - reference: DOI:10.1128/aem.63.4.1274-1283.1997 snippet: The phage resistance mechanism encoded on pSRQ800 is a temperature-sensitive abortive infection system (Abi) notes: Emond et al. localized a lactococcal plasmid-encoded abortive-infection mechanism that strongly resists 936 and P335 phages. - reference: DOI:10.1128/aem.63.4.1274-1283.1997 snippet: orf1 (renamed abiK) coded for a predicted protein of 599 amino acids (AbiK) notes: Emond et al. identified abiK as the open reading frame needed for the pSRQ800 Abi phenotype. - reference: DOI:10.1128/aem.63.4.1274-1283.1997 snippet: No phage DNA replication nor phage structural protein production was detected in infected AbiK+ L. lactis cells notes: Emond et al. support an AbiK-associated block at or before DNA replication for the ul36 lactococcal phage. - reference: DOI:10.1099/00221287-146-2-445 snippet: Only immature forms (concatemeric and circular DNA) of phage p2 DNA were found, indicating that the presence of AbiK prevented phage DNA maturation notes: Boucher et al. show that AbiK can block later DNA maturation rather than DNA replication itself, depending on the lactococcal phage tested. - reference: DOI:10.1128/JB.187.11.3721-3730.2005 snippet: the antiphage activity depends on the level of expression of the abiK gene and on the presence of a reverse transcriptase (RT) motif in AbiK notes: Fortier et al. connect AbiK phage resistance to conserved reverse-transcriptase motifs in the AbiK protein. - reference: DOI:10.1128/JB.187.11.3721-3730.2005 snippet: Conservative mutations in key positions resulted in the complete loss of the resistance phenotype notes: Fortier et al. mutated AbiK RT motifs and showed that key positions are necessary for AbiK-mediated resistance. - reference: DOI:10.1093/nar/gkr397 snippet: AbiK does not exhibit the properties expected for an RT, but polymerizes long DNAs of ‘random’ sequence, analogous to a terminal transferase notes: Wang et al. biochemically characterized AbiK as an RT-related polymerase with template-independent DNA polymerization activity. - reference: DOI:10.1093/nar/gkr397 snippet: Mutagenesis experiments indicate that the polymerase activity resides in the RT motifs and is essential for phage resistance in vivo notes: Wang et al. support AbiK RT-motif polymerase activity as an essential contributor to phage resistance. canonical_examples: - taxon_id: NCBITaxon:1358 taxon_label: Lactococcus lactis note: Emond et al. isolated the pSRQ800 abiK determinant from Lactococcus lactis subsp. lactis W1 and showed that it confers abortive infection against 936 and P335 lactococcal phages when introduced into phage-sensitive Lactococcus lactis strains. reference: DOI:10.1128/aem.63.4.1274-1283.1997 causal_graphs: - graph_id: abik_rt_polymerase_antiphage_activity title: AbiK RT-related polymerase activity restricts lactococcal phages description: Evidence-backed process sketch linking an abiK locus to AbiK RT-related polymerase activity, phage DNA replication or maturation blocks, restricted phage propagation, and abortive-infection system possession. scope_status: NONMECHANISTIC scope_notes: The graph captures AbiK at the system level without asserting the natural AbiK DNA primer or product, the endogenous polymerase substrate, or one universal DNA-stage block for all sensitive phages. nodes: - node_id: abik_locus label: abiK locus node_type: GENETIC_ELEMENT description: An abortive-infection locus encoding the AbiK RT-related polymerase. - node_id: abik_rt_polymerase_activity label: AbiK RT-related polymerase activity node_type: MOLECULAR_FUNCTION description: Reverse-transcriptase-motif-dependent DNA polymerase activity of AbiK. - node_id: interrupted_phage_dna_replication_or_maturation label: interrupted phage DNA replication or maturation node_type: BIOLOGICAL_PROCESS description: Phage-specific interruption of DNA replication or DNA maturation in AbiK-containing infected Lactococcus cells. - node_id: restricted_phage_propagation label: restricted phage propagation node_type: BIOLOGICAL_PROCESS description: Reduced completion of 936 or P335 phage propagation in an AbiK-containing infected host cell. - node_id: abik_system_trait label: AbiK system node_type: TRAIT grounding: traitmech:000229 description: Possession of a genome-encoded AbiK RT-related 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: abik_locus predicate: contributes to predicate_id: RO:0002326 object: abik_rt_polymerase_activity description: The abiK locus encodes an AbiK protein whose conserved RT motifs support antiphage activity. evidence: - reference: DOI:10.1128/JB.187.11.3721-3730.2005 snippet: the antiphage activity depends on the level of expression of the abiK gene and on the presence of a reverse transcriptase (RT) motif in AbiK notes: Fortier et al. connect abiK expression and AbiK RT motifs to the phage-resistance phenotype. - subject: abik_rt_polymerase_activity predicate: contributes to predicate_id: RO:0002326 object: restricted_phage_propagation description: AbiK RT-motif polymerase activity is required for the in vivo phage-resistance phenotype. evidence: - reference: DOI:10.1093/nar/gkr397 snippet: Mutagenesis experiments indicate that the polymerase activity resides in the RT motifs and is essential for phage resistance in vivo notes: Wang et al. showed that AbiK RT motifs carry the in vitro polymerase activity and are essential for phage resistance in vivo. - subject: abik_locus predicate: contributes to predicate_id: RO:0002326 object: interrupted_phage_dna_replication_or_maturation description: The AbiK determinant produces a phage-specific block at DNA replication or DNA maturation. evidence: - reference: DOI:10.1099/00221287-146-2-445 snippet: Only immature forms (concatemeric and circular DNA) of phage p2 DNA were found, indicating that the presence of AbiK prevented phage DNA maturation notes: Boucher et al. found immature DNA forms for phage p2 and compared that phenotype with the earlier ul36 DNA-replication block. - subject: interrupted_phage_dna_replication_or_maturation predicate: contributes to predicate_id: RO:0002326 object: restricted_phage_propagation description: Interrupting DNA replication or maturation limits completion of the phage lytic cycle. evidence: - reference: DOI:10.1128/aem.63.4.1274-1283.1997 snippet: No phage DNA replication nor phage structural protein production was detected in infected AbiK+ L. lactis cells notes: Emond et al. show that AbiK prevents ul36 DNA replication and structural-protein production in infected Lactococcus lactis. - subject: restricted_phage_propagation predicate: confers predicate_id: METPO:2007700 object: abik_system_trait description: Restriction of 936/P335 phage propagation realizes the AbiK abortive-infection defense trait. evidence: - reference: DOI:10.1128/aem.63.4.1274-1283.1997 snippet: The phage resistance mechanism encoded on pSRQ800 is a temperature-sensitive abortive infection system (Abi) notes: Emond et al. define the pSRQ800 AbiK determinant as an abortive-infection phage resistance system. - subject: abik_system_trait predicate: is a predicate_id: rdfs:subClassOf object: abortive_infection_system_trait description: AbiK system possession is an abortive-infection-system trait. evidence: - reference: DOI:10.1093/nar/gkr397 snippet: AbiK, which is required for abortive phage infection in the Gram-positive bacterium Lactococcus lactis notes: Wang et al. place AbiK in the abortive infection class of phage defense. curation_history: - timestamp: '2026-09-15T21:30:00Z' curator: codex action: MINTED_TRAITMECH_ID changes: Minted AbiK 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_v106. llm_assisted: true