identifier: traitmech:000314
label: 6A-MBL system
definition: A phage defense system in which an organism possesses a 6A-MBL locus that
  can protect bacteria from bacteriophage infection.
definition_source: DOI:10.1016/j.chom.2024.07.007
trait_category: GENOMICS
term_kind: CLASS
mapping_status: PROPOSED
parent_traits:
- traitmech:000209
synonyms:
- synonym_text: 6A-MBL
  synonym_type: EXACT_SYNONYM
  source: https://zenodo.org/records/11209165
- synonym_text: 6A_MBL
  synonym_type: RELATED_SYNONYM
  source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md
- synonym_text: cap2_3
  synonym_type: RELATED_SYNONYM
  source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
- synonym_text: MblB
  synonym_type: RELATED_SYNONYM
  source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
evidence:
- reference: DOI:10.1016/j.chom.2024.07.007
  snippet: We validated six of these phage defense systems, including factors preventing
    viral attachment, R-loop-acting enzymes, the inflammasome, ubiquitin pathway,
    and pathogen recognition signaling.
  notes: van den Berg et al. validated six phage defense systems related to eukaryotic
    innate antiviral responses.
- reference: DOI:10.1016/j.chom.2024.07.007
  snippet: Searching for phage defense systems related to innate antiviral genes from
    vertebrates and plants, we uncovered over 450 candidates.
  notes: van den Berg et al. motivate a conservative system-level record that does
    not assert a resolved 6A-MBL trigger, effector output, or universal pathway.
- reference: https://zenodo.org/records/11209165
  snippet: In addition, a fused ubiquitin-like E1-E2-JAB protein combined with a putative
    MBL nuclease (6A-MBL) was found
  notes: The Zenodo manuscript/supplementary-data record from van den Berg et al.
    names 6A-MBL as a putative MBL-nuclease system candidate.
- reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md
  snippet: 6A_MBL | 10\.1016/j\.chom\.2024\.07\.007 | Bacterial homologs of innate
    eukaryotic antiviral defenses with anti-phage activity highlight shared evolutionary
    roots of viral defenses
  notes: The DefenseFinder article registry maps the named 6A-MBL system to the van
    den Berg et al. antiphage-system discovery paper.
- reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
  snippet: 6A_MBL__cap2_3                                   |                                                  |
    6A_MBL
  notes: The DefenseFinder HMM inventory records 6A_MBL__cap2_3 as a cap2_3 profile
    in the 6A_MBL model namespace.
- reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
  snippet: 6A_MBL__MblB                                     |                                                  |
    6A_MBL
  notes: The DefenseFinder HMM inventory records 6A_MBL__MblB as a MblB profile in
    the 6A_MBL model namespace.
causal_graphs:
- graph_id: six_a_mbl_locus_restricts_phage
  title: 6A-MBL loci confer bacterial phage defense
  description: Conservative system-level sketch linking possession of a 6A-MBL locus
    to restricted bacteriophage propagation without asserting the unresolved phage
    trigger or molecular output.
  scope_status: NONMECHANISTIC
  scope_notes: The graph captures 6A-MBL as a named anti-phage system with 6A_MBL__cap2_3
    and 6A_MBL__MblB DefenseFinder HMM profile entries while leaving its phage trigger,
    molecular substrate, antiviral effector output, and subtype breadth unresolved.
  nodes:
  - node_id: six_a_mbl_locus
    label: 6A-MBL locus
    node_type: GENETIC_ELEMENT
    description: A 6A-MBL anti-phage defense locus cataloged in DefenseFinder with
      cap2_3 and MblB HMM profile entries.
  - node_id: restricted_phage_propagation
    label: restricted phage propagation
    node_type: BIOLOGICAL_PROCESS
    description: Reduced propagation of bacteriophage in cells carrying the 6A-MBL
      system.
  - node_id: six_a_mbl_system_trait
    label: 6A-MBL system
    node_type: TRAIT
    grounding: traitmech:000314
    description: Possession of a genome-encoded 6A-MBL 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: six_a_mbl_locus
    predicate: contributes to
    predicate_id: RO:0002326
    object: restricted_phage_propagation
    description: DefenseFinder maps 6A_MBL to a eukaryotic-antiviral-homolog antiphage-system
      discovery paper and catalogs cap2_3 and MblB HMM profile entries in the 6A_MBL
      model namespace.
    evidence:
    - reference: DOI:10.1016/j.chom.2024.07.007
      snippet: We validated six of these phage defense systems, including factors
        preventing viral attachment, R-loop-acting enzymes, the inflammasome, ubiquitin
        pathway, and pathogen recognition signaling.
      notes: van den Berg et al. validated six phage defense systems related to eukaryotic
        innate antiviral responses.
    - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md
      snippet: 6A_MBL | 10\.1016/j\.chom\.2024\.07\.007 | Bacterial homologs of innate
        eukaryotic antiviral defenses with anti-phage activity highlight shared evolutionary
        roots of viral defenses
      notes: The DefenseFinder article registry maps the named 6A-MBL system to the
        van den Berg et al. antiphage-system discovery paper.
    - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
      snippet: 6A_MBL__cap2_3                                   |                                                  |
        6A_MBL
      notes: The DefenseFinder HMM inventory records 6A_MBL__cap2_3 as a cap2_3 profile
        in the 6A_MBL model namespace.
    - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
      snippet: 6A_MBL__MblB                                     |                                                  |
        6A_MBL
      notes: The DefenseFinder HMM inventory records 6A_MBL__MblB as a MblB profile
        in the 6A_MBL model namespace.
  - subject: restricted_phage_propagation
    predicate: confers
    predicate_id: METPO:2007700
    object: six_a_mbl_system_trait
    description: 6A-MBL-mediated phage restriction realizes the 6A-MBL system trait.
    evidence:
    - reference: DOI:10.1016/j.chom.2024.07.007
      snippet: We validated six of these phage defense systems, including factors
        preventing viral attachment, R-loop-acting enzymes, the inflammasome, ubiquitin
        pathway, and pathogen recognition signaling.
      notes: van den Berg et al. validated six phage defense systems related to eukaryotic
        innate antiviral responses.
  - subject: six_a_mbl_system_trait
    predicate: is a
    predicate_id: rdfs:subClassOf
    object: phage_defense_system
    description: 6A-MBL system possession is a phage-defense-system trait.
    evidence:
    - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md
      snippet: 6A_MBL | 10\.1016/j\.chom\.2024\.07\.007 | Bacterial homologs of innate
        eukaryotic antiviral defenses with anti-phage activity highlight shared evolutionary
        roots of viral defenses
      notes: The DefenseFinder article registry maps the named 6A-MBL system to the
        van den Berg et al. antiphage-system discovery paper.
discussions:
- discussion_id: six-a-mbl-mechanism-gap
  prompt: Resolve 6A-MBL phage triggers and effector outputs before minting narrower
    6A-MBL mechanism children.
  kind: KNOWLEDGE_GAP
  status: OPEN
  rationale: van den Berg et al. and DefenseFinder support 6A-MBL as a named anti-phage
    system with 6A_MBL__cap2_3 and 6A_MBL__MblB HMM profile entries, but the trigger,
    molecular substrate, antiviral effector output, and subtype-specific mechanism
    are not resolved enough here to assert a narrower mechanistic child trait.
  attaches_to:
  - causal_graphs#six_a_mbl_locus_restricts_phage
  posed_by: codex
  posed_date: '2026-09-20'
curation_history:
- timestamp: '2026-09-20T16:42:08Z'
  curator: codex
  action: MINTED_TRAITMECH_ID
  changes: Minted 6A-MBL 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_v191.
  llm_assisted: true
- timestamp: '2026-09-20T16:43:08Z'
  curator: codex
  action: REVIEW_CANONICAL_EXAMPLE_EVIDENCE_GAP
  changes: 'Reviewed the 6A-MBL canonical_examples gap and left canonical_examples
    empty: the current evidence supports a named phage-defense system and DefenseFinder
    profiles, but the curated record does not yet cite a source-backed bacterial taxon
    with a directly observed 6A-MBL locus. No paid research was used.'
  llm_assisted: true
- timestamp: '2026-09-20T17:16:31Z'
  curator: codex
  action: CURATION_REVIEW_REVISION
  changes: 'Resolved issue #1148 by sourcing the exact 6A-MBL synonym from the stable
    van den Berg Zenodo record that names 6A-MBL verbatim, leaving DefenseFinder model
    and component labels as related synonyms.'
  llm_assisted: true