Brc22 system

traitmech:000523 · CLASS · PROPOSED

A phage defense system in which an organism possesses a gcu22/Brc22 bacteriophage-resistance integron cassette that supports growth during bacteriophage challenge.

Trait evidence (7)

DOI:10.1126/science.ads0915
Gcu22 conferred low levels of resistance exclusively against phage F13 in K. pneumoniae

Kieffer et al. report that the former gcu22 cassette conferred low-level F13 resistance in Klebsiella pneumoniae.
DOI:10.1126/science.ads0915
We therefore redefined both cassettes as BRiCs (brc22 and brc23)

Kieffer et al. renamed gcu22 and gcu23 as Brc cassettes after phage-resistance testing.
DOI:10.1126/science.ads0915
Predicted secondary structures of attC sites in identified BRiCs

Kieffer et al. identify BRiC bacteriophage-resistance integron cassettes and show their predicted attC secondary structures.
DOI:10.1126/science.ads0915
brc113 brc217 brc76 brcWGS21 brc22 brc23

Kieffer et al. include brc22 among identified BRiCs with predicted attC secondary structures.
https://www.science.org/doi/suppl/10.1126/science.ads0915/suppl_file/science.ads0915_sm.pdf
attC of brc22, with a perfect GTT/AAC binding between both arms of the stem

Kieffer et al. discuss the brc22 attC site in a comparison of Tragantia homolog-associated predicted secondary structures.
https://www.science.org/doi/suppl/10.1126/science.ads0915/suppl_file/science.ads0915_sm.pdf
D278 pMBA PcW brc22 E. coli IJ1862

Kieffer et al.'s supplementary construct table lists pMBA PcW brc22 in E. coli IJ1862 under naturally occurring defense island constructs.
https://www.science.org/doi/suppl/10.1126/science.ads0915/suppl_file/science.ads0915_sm.pdf
D283 pMBA PcW brc22 K. pneumoniae KP5

Kieffer et al.'s supplementary construct table lists pMBA PcW brc22 in Klebsiella pneumoniae KP5 under naturally occurring defense island constructs.

Brc22 BRiCs confer phage resistance

Conservative system-level sketch linking a gcu22/Brc22 bacteriophage-resistance integron cassette to phage resistance and Brc22 system possession.

NONMECHANISTIC · The graph captures Brc22 at the integron-cassette and phage-resistance-output level without asserting the native host range, exact sensitive-phage breadth, direct molecular substrate, whether Brc22 and Brc23 are variants of one Tragantia family, or a DefenseFinder article/HMM/rules profile absent from the pinned snapshot.

Edge evidence

Brc22 integron cassette contributes to Brc22 phage resistance RO:0002326
The gcu22/Brc22 integron cassette contributes to F13 phage resistance during phage-panel assays in Klebsiella pneumoniae.
- DOI:10.1126/science.ads0915 Gcu22 conferred low levels of resistance exclusively against phage F13 in K. pneumoniae Kieffer et al. report that the former gcu22 cassette conferred low-level F13 resistance in Klebsiella pneumoniae.
Brc22 phage resistance confers Brc22 system METPO:2007700
Brc22-linked phage resistance realizes the Brc22 system possession trait.
- DOI:10.1126/science.ads0915 Gcu22 conferred low levels of resistance exclusively against phage F13 in K. pneumoniae Kieffer et al. report that the former gcu22 cassette conferred low-level F13 resistance in Klebsiella pneumoniae.
- DOI:10.1126/science.ads0915 We therefore redefined both cassettes as BRiCs (brc22 and brc23) Kieffer et al. renamed gcu22 and gcu23 as Brc cassettes after phage-resistance testing.
Brc22 system is a phage defense system rdfs:subClassOf
Brc22 system possession is a phage-defense-system trait.
- DOI:10.1126/science.ads0915 Predicted secondary structures of attC sites in identified BRiCs Kieffer et al. identify BRiC bacteriophage-resistance integron cassettes and show their predicted attC secondary structures.
- DOI:10.1126/science.ads0915 brc113 brc217 brc76 brcWGS21 brc22 brc23 Kieffer et al. include brc22 among identified BRiCs with predicted attC secondary structures.

Provenance

Identifier source: TraitMech local identifier
Definition source: DOI:10.1126/science.ads0915

Parent traits (1)

phage defense system traitmech:000209

Synonyms (2)

gcu22 RELATED_SYNONYM · DOI:10.1126/science.ads0915
brc22 RELATED_SYNONYM · DOI:10.1126/science.ads0915

kg-microbe context

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

Discussions and Knowledge Gaps (1)

Open questions attached to this trait. Seeded by just knowledge-gap-scan and curated; see the corpus-wide index.

Resolve Brc22 native host breadth, exact sensitive-phage breadth, molecular output, Tragantia-family boundaries, and DefenseFinder article/HMM/rules coverage before minting narrower Brc22 mechanism children.

KNOWLEDGE GAP OPEN brc22-defensefinder-model-gap · raised by codex · 2026-10-01

Attached to causal_graphs#brc22_integron_cassette_confers_phage_resistance

Kieffer et al. identify brc22 as a bacteriophage-resistance integron cassette. The pinned DefenseFinder article registry, HMM inventory, and rules table have no exact gcu22 or Brc22 row, so the first-pass record leaves native-host breadth, profile boundaries, exact phage target breadth, direct molecular output, and Brc22/Brc23 Tragantia-family scope unresolved.

Evidence

DOI:10.1126/science.ads0915
Gcu22 conferred low levels of resistance exclusively against phage F13 in K. pneumoniae
DOI:10.1126/science.ads0915
We therefore redefined both cassettes as BRiCs (brc22 and brc23)
DOI:10.1126/science.ads0915
Predicted secondary structures of attC sites in identified BRiCs
DOI:10.1126/science.ads0915
brc113 brc217 brc76 brcWGS21 brc22 brc23
https://www.science.org/doi/suppl/10.1126/science.ads0915/suppl_file/science.ads0915_sm.pdf
attC of brc22, with a perfect GTT/AAC binding between both arms of the stem
https://www.science.org/doi/suppl/10.1126/science.ads0915/suppl_file/science.ads0915_sm.pdf
D278 pMBA PcW brc22 E. coli IJ1862
https://www.science.org/doi/suppl/10.1126/science.ads0915/suppl_file/science.ads0915_sm.pdf
D283 pMBA PcW brc22 K. pneumoniae KP5
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv

Curation history

2026-10-01T19:20:00Z · MINTED_TRAITMECH_ID · codex
Minted Brc22 system as a DOI-backed GENOMICS TraitRecord under phage defense system after an ignored-and-hidden duplicate review ruled out same-scope live TraitMech, METPO, history, and prior proposal collisions after reviewing exact Brc22/brc22/gcu22 hits; kept the graph at BRiC integron-cassette level because the pinned DefenseFinder article registry, HMM inventory, and rules table have no exact Brc22 row; the replacement placeholder is reserved in proposals/metpo_traitmech_v400.
2026-10-01T19:20:01Z · REVIEW_CANONICAL_EXAMPLE_EVIDENCE_GAP · codex
Reviewed Brc22 system during initial curation and left canonical_examples empty because the sources support heterologous gcu22/Brc22 phage-resistance assays but not a direct named native microbial isolate exemplar with experimentally verified endogenous Brc22 activity. No paid research was used.