identifier: traitmech:000369 label: Bil system definition: A phage defense system in which an organism possesses a Bil bacterial ubiquitin-like conjugation locus that can covalently attach a ubiquitin-like protein to the bacteriophage central tail fibre and impair phage infectivity. definition_source: DOI:10.1038/s41586-024-07616-5 trait_category: GENOMICS term_kind: CLASS mapping_status: PROPOSED parent_traits: - traitmech:000209 synonyms: - synonym_text: Bil synonym_type: EXACT_SYNONYM source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md - synonym_text: Bil antiphage defence system synonym_type: EXACT_SYNONYM source: DOI:10.1038/s41586-024-07616-5 evidence: - reference: DOI:10.1038/s41586-024-07616-5 snippet: Bil antiphage defence system notes: Hor et al. identify Bil as a ubiquitin-like conjugation antiphage defense system. - reference: DOI:10.1038/s41586-024-07616-5 snippet: phage central tail fibre is obstructed by the covalently attached ubiquitin-like protein notes: Hor et al. show that the Bil system obstructs the phage central tail fibre with a covalently attached ubiquitin-like protein. - reference: DOI:10.1038/s41586-024-07616-5 snippet: These phages show severely impaired infectivity notes: Hor et al. connect Bil-dependent particle production to reduced phage infectivity. - reference: DOI:10.1016/j.chom.2022.09.017 snippet: An expanded arsenal of immune systems that protect bacteria from phages notes: Millman et al. published the discovery cohort that DefenseFinder maps to its Bil article-registry row. - reference: DOI:10.1101/2022.05.11.491447 snippet: An expanding arsenal of immune systems that protect bacteria from phages notes: The bioRxiv version of Millman et al. is the DOI cited in DefenseFinder's Bil article-registry row. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: Bil | 10\.1101/2022\.05\.11\.491447 | An expanding arsenal of immune systems that protect bacteria from phages notes: The DefenseFinder article registry maps the named Bil system to the Millman et al. antiphage-system discovery preprint. causal_graphs: - graph_id: bil_locus_impairs_phage_assembly title: Bil loci impair bacteriophage infectivity description: Conservative system-level sketch linking possession of a Bil ubiquitin-like conjugation locus to central-tail-fibre obstruction and impaired phage infectivity without asserting the exact DefenseFinder profile or rule set for Bil. scope_status: NONMECHANISTIC scope_notes: The graph captures Bil as a named phage-defense system whose ubiquitin-like protein is covalently attached to the phage central tail fibre while leaving the exact Bil component composition, target-phage breadth, receptor-recognition consequences, and DefenseFinder model profiles unresolved. nodes: - node_id: bil_locus label: Bil locus node_type: GENETIC_ELEMENT description: A bacterial Bil ubiquitin-like conjugation locus that encodes an antiphage defense system. - node_id: bil_ubiquitin_like_conjugation label: Bil ubiquitin-like conjugation node_type: BIOLOGICAL_PROCESS description: Covalent attachment of a Bil ubiquitin-like protein during phage infection. - node_id: central_tail_fibre_obstruction label: central tail fibre obstruction node_type: BIOLOGICAL_PROCESS description: Obstruction of a bacteriophage central tail fibre by a covalently attached ubiquitin-like protein. - node_id: impaired_phage_infectivity label: impaired phage infectivity node_type: BIOLOGICAL_PROCESS description: Reduced infectivity of phage particles released from cells encoding the Bil defense system. - node_id: bil_system_trait label: Bil system node_type: TRAIT grounding: traitmech:000369 description: Possession of a genome-encoded Bil 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: bil_locus predicate: contributes to predicate_id: RO:0002326 object: bil_ubiquitin_like_conjugation description: Bil loci encode a bacterial antiphage system based on ubiquitin-like conjugation, and DefenseFinder links Bil to an antiphage-system discovery preprint. evidence: - reference: DOI:10.1038/s41586-024-07616-5 snippet: Bil antiphage defence system notes: Hor et al. identify Bil as a ubiquitin-like conjugation antiphage defense system. - reference: DOI:10.1016/j.chom.2022.09.017 snippet: An expanded arsenal of immune systems that protect bacteria from phages notes: Millman et al. published the discovery cohort that DefenseFinder maps to its Bil article-registry row. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: Bil | 10\.1101/2022\.05\.11\.491447 | An expanding arsenal of immune systems that protect bacteria from phages notes: The DefenseFinder article registry maps the named Bil system to the Millman et al. antiphage-system discovery preprint. - subject: bil_ubiquitin_like_conjugation predicate: contributes to predicate_id: RO:0002326 object: central_tail_fibre_obstruction description: The Bil system can obstruct the phage central tail fibre by covalently attaching a ubiquitin-like protein. evidence: - reference: DOI:10.1038/s41586-024-07616-5 snippet: phage central tail fibre is obstructed by the covalently attached ubiquitin-like protein notes: Hor et al. show that the Bil system obstructs the phage central tail fibre with a covalently attached ubiquitin-like protein. - subject: central_tail_fibre_obstruction predicate: contributes to predicate_id: RO:0002326 object: impaired_phage_infectivity description: Central-tail-fibre obstruction by the Bil system impairs phage-particle infectivity. evidence: - reference: DOI:10.1038/s41586-024-07616-5 snippet: phage central tail fibre is obstructed by the covalently attached ubiquitin-like protein notes: Hor et al. show that the Bil system obstructs the phage central tail fibre with a covalently attached ubiquitin-like protein. - reference: DOI:10.1038/s41586-024-07616-5 snippet: These phages show severely impaired infectivity notes: Hor et al. connect Bil-dependent particle production to reduced phage infectivity. - subject: impaired_phage_infectivity predicate: confers predicate_id: METPO:2007700 object: bil_system_trait description: Bil-mediated impairment of phage infectivity realizes the Bil system trait. evidence: - reference: DOI:10.1038/s41586-024-07616-5 snippet: These phages show severely impaired infectivity notes: Hor et al. connect Bil-dependent particle production to reduced phage infectivity. - subject: bil_system_trait predicate: is a predicate_id: rdfs:subClassOf object: phage_defense_system description: Bil system possession is a phage-defense-system trait. evidence: - reference: DOI:10.1038/s41586-024-07616-5 snippet: Bil antiphage defence system notes: Hor et al. identify Bil as a ubiquitin-like conjugation antiphage defense system. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: Bil | 10\.1101/2022\.05\.11\.491447 | An expanding arsenal of immune systems that protect bacteria from phages notes: The DefenseFinder article registry maps the named Bil system to the Millman et al. antiphage-system discovery preprint. discussions: - discussion_id: bil-defensefinder-profile-gap prompt: Resolve Bil HMM profiles and rule rows before minting component-specific Bil mechanism children. kind: KNOWLEDGE_GAP status: OPEN rationale: Hor et al. support Bil as a bacterial ubiquitin-like conjugation antiphage system that modifies the phage central tail fibre, and the pinned DefenseFinder article registry maps Bil to the Millman et al. discovery preprint. The same pinned HMM inventory and rules table do not include exact Bil rows, so the exact DefenseFinder profile set, component rule, and model coverage remain unresolved. evidence: - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: Bil | 10\.1101/2022\.05\.11\.491447 | An expanding arsenal of immune systems that protect bacteria from phages notes: The DefenseFinder article registry maps the named Bil system to the Millman et al. antiphage-system discovery preprint. attaches_to: - causal_graphs#bil_locus_impairs_phage_assembly posed_by: codex posed_date: '2026-09-24' curation_history: - timestamp: '2026-09-25T03:02:00Z' curator: codex action: MINTED_TRAITMECH_ID changes: Minted Bil 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_v246. llm_assisted: true - timestamp: '2026-09-25T03:03:00Z' curator: codex action: REVIEW_DEFENSEFINDER_PROFILE_GAP changes: Reviewed the DefenseFinder Bil article-registry row at commit afb0e5a8b466be53586b13266f5d38d98c3ac268 and left narrower Bil HMM/profile semantics unresolved because the pinned HMM inventory and rules table have no exact Bil rows. llm_assisted: true