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AbiK system

traitmech:000229 · CLASS · PROPOSED

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.

Trait evidence (8)

  • DOI:10.1128/aem.63.4.1274-1283.1997
    The phage resistance mechanism encoded on pSRQ800 is a temperature-sensitive abortive infection system (Abi)

    Emond et al. localized a lactococcal plasmid-encoded abortive-infection mechanism that strongly resists 936 and P335 phages.

  • DOI:10.1128/aem.63.4.1274-1283.1997
    orf1 (renamed abiK) coded for a predicted protein of 599 amino acids (AbiK)

    Emond et al. identified abiK as the open reading frame needed for the pSRQ800 Abi phenotype.

  • DOI:10.1128/aem.63.4.1274-1283.1997
    No phage DNA replication nor phage structural protein production was detected in infected AbiK+ L. lactis cells

    Emond et al. support an AbiK-associated block at or before DNA replication for the ul36 lactococcal phage.

  • DOI:10.1099/00221287-146-2-445
    Only immature forms (concatemeric and circular DNA) of phage p2 DNA were found, indicating that the presence of AbiK prevented phage DNA maturation

    Boucher et al. show that AbiK can block later DNA maturation rather than DNA replication itself, depending on the lactococcal phage tested.

  • DOI:10.1128/JB.187.11.3721-3730.2005
    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

    Fortier et al. connect AbiK phage resistance to conserved reverse-transcriptase motifs in the AbiK protein.

  • DOI:10.1128/JB.187.11.3721-3730.2005
    Conservative mutations in key positions resulted in the complete loss of the resistance phenotype

    Fortier et al. mutated AbiK RT motifs and showed that key positions are necessary for AbiK-mediated resistance.

  • DOI:10.1093/nar/gkr397
    AbiK does not exhibit the properties expected for an RT, but polymerizes long DNAs of ‘random’ sequence, analogous to a terminal transferase

    Wang et al. biochemically characterized AbiK as an RT-related polymerase with template-independent DNA polymerization activity.

  • DOI:10.1093/nar/gkr397
    Mutagenesis experiments indicate that the polymerase activity resides in the RT motifs and is essential for phage resistance in vivo

    Wang et al. support AbiK RT-motif polymerase activity as an essential contributor to phage resistance.

AbiK RT-related polymerase activity restricts lactococcal phages

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.

NONMECHANISTIC · 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.

AbiK RT-related polymerase activity restricts lactococcal phages Interactive directed graph showing evidence-backed causal relationships for AbiK system.

Edge evidence

  • abiK locus contributes to AbiK RT-related polymerase activity RO:0002326

    The abiK locus encodes an AbiK protein whose conserved RT motifs support antiphage activity.

    • DOI:10.1128/JB.187.11.3721-3730.2005 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 Fortier et al. connect abiK expression and AbiK RT motifs to the phage-resistance phenotype.
  • AbiK RT-related polymerase activity contributes to restricted phage propagation RO:0002326

    AbiK RT-motif polymerase activity is required for the in vivo phage-resistance phenotype.

    • DOI:10.1093/nar/gkr397 Mutagenesis experiments indicate that the polymerase activity resides in the RT motifs and is essential for phage resistance in vivo Wang et al. showed that AbiK RT motifs carry the in vitro polymerase activity and are essential for phage resistance in vivo.
  • abiK locus contributes to interrupted phage DNA replication or maturation RO:0002326

    The AbiK determinant produces a phage-specific block at DNA replication or DNA maturation.

    • DOI:10.1099/00221287-146-2-445 Only immature forms (concatemeric and circular DNA) of phage p2 DNA were found, indicating that the presence of AbiK prevented phage DNA maturation Boucher et al. found immature DNA forms for phage p2 and compared that phenotype with the earlier ul36 DNA-replication block.
  • interrupted phage DNA replication or maturation contributes to restricted phage propagation RO:0002326

    Interrupting DNA replication or maturation limits completion of the phage lytic cycle.

    • DOI:10.1128/aem.63.4.1274-1283.1997 No phage DNA replication nor phage structural protein production was detected in infected AbiK+ L. lactis cells Emond et al. show that AbiK prevents ul36 DNA replication and structural-protein production in infected Lactococcus lactis.
  • restricted phage propagation confers AbiK system METPO:2007700

    Restriction of 936/P335 phage propagation realizes the AbiK abortive-infection defense trait.

    • DOI:10.1128/aem.63.4.1274-1283.1997 The phage resistance mechanism encoded on pSRQ800 is a temperature-sensitive abortive infection system (Abi) Emond et al. define the pSRQ800 AbiK determinant as an abortive-infection phage resistance system.
  • AbiK system is a abortive infection system rdfs:subClassOf

    AbiK system possession is an abortive-infection-system trait.

    • DOI:10.1093/nar/gkr397 AbiK, which is required for abortive phage infection in the Gram-positive bacterium Lactococcus lactis Wang et al. place AbiK in the abortive infection class of phage defense.

Provenance

Identifier source
TraitMech local identifier
Definition source
DOI:10.1128/aem.63.4.1274-1283.1997

Parent traits (1)

kg-microbe context

No kg-microbe node embedding matched this record in the 2026-04-25 deepwalk.

Canonical examples (1)

Organisms cited as exemplars of this trait. Taxon ids are NCBITaxon and link out to the NCBI record.

  • Lactococcus lactis NCBITaxon:1358 DOI:10.1128/aem.63.4.1274-1283.1997 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.

Curation history

  1. · MINTED_TRAITMECH_ID · codex

    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.