RexAB system

traitmech:000324 · CLASS · PROPOSED

An abortive infection system in which an organism possesses a bacteriophage-lambda Rex-family locus represented by the DefenseFinder RexAB__RexA and RexAB__RexB profiles and exemplified by the rexA and rexB two-component system that aborts lytic growth of bacterial viruses.

Trait evidence (6)

DOI:10.1101/gad.6.3.497
The rexA and rexB genes of bacteriophage lambda encode a two-component system that aborts lytic growth of bacterial viruses.

Parma et al. support RexA and RexB as a two-component Rex exclusion system.
DOI:10.1101/gad.6.3.497
Rex exclusion is characterized by termination of macromolecular synthesis, loss of active transport, the hydrolysis of ATP, and cell death.

Parma et al. support Rex exclusion as an abortive-infection-like output with host-cell death.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md
RexAB | 10\.1101/gad\.6\.3\.497 | The Rex system of bacteriophage lambda: tolerance and altruistic cell death

The DefenseFinder article registry maps the named RexAB model namespace to the bacteriophage-lambda Rex system paper.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv
RexAB RexAB 2 2 RexAB__RexA, RexAB__RexB

The DefenseFinder rules table models RexAB as a two-component system requiring the RexA and RexB profiles.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
| RexAB__RexA | RexAB__RexA | RexAB | PF15969.7 | 25 |

The DefenseFinder HMM inventory records RexAB__RexA under RexAB.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
| RexAB__RexB | RexAB__RexB | RexAB | PF15968.7 | 27 |

The DefenseFinder HMM inventory records RexAB__RexB under RexAB.

RexAB loci mediate abortive Rex exclusion

Conservative system-level sketch linking RexA/RexB locus possession to Rex exclusion and RexAB-system possession without asserting the direct phage trigger, RexA/RexB stoichiometry, membrane target, or bacteriophage-lambda self-protection route.

NONMECHANISTIC · The graph captures RexAB as a named DefenseFinder two-profile abortive-infection system whose lambda prototype aborts lytic growth. It leaves the direct phage trigger, RexA/RexB molecular coupling, ion-channel activity, self-exclusion control, and phage escape routes unresolved.

Edge evidence

RexAB locus contributes to Rex exclusion RO:0002326
The bacteriophage-lambda RexA/RexB system aborts lytic growth of bacterial viruses, and DefenseFinder represents RexAB with required RexA and RexB profiles.
- DOI:10.1101/gad.6.3.497 The rexA and rexB genes of bacteriophage lambda encode a two-component system that aborts lytic growth of bacterial viruses. Parma et al. support RexA and RexB as the core genetic components of Rex exclusion.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv RexAB RexAB 2 2 RexAB__RexA, RexAB__RexB The DefenseFinder rules table models RexAB as a two-component system requiring the RexA and RexB profiles.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md | RexAB__RexA | RexAB__RexA | RexAB | PF15969.7 | 25 | The DefenseFinder HMM inventory records RexAB__RexA under RexAB.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md | RexAB__RexB | RexAB__RexB | RexAB | PF15968.7 | 27 | The DefenseFinder HMM inventory records RexAB__RexB under RexAB.
Rex exclusion confers RexAB system METPO:2007700
RexA/RexB-dependent abortive exclusion realizes the RexAB system trait.
- DOI:10.1101/gad.6.3.497 Rex exclusion is characterized by termination of macromolecular synthesis, loss of active transport, the hydrolysis of ATP, and cell death. Parma et al. connect Rex exclusion to host-cell shutdown and death.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md RexAB | 10\.1101/gad\.6\.3\.497 | The Rex system of bacteriophage lambda: tolerance and altruistic cell death The DefenseFinder article registry maps the named RexAB model namespace to the bacteriophage-lambda Rex system paper.

Provenance

Identifier source: TraitMech local identifier
Definition source: DOI:10.1101/gad.6.3.497

Parent traits (1)

abortive infection system traitmech:000214

Synonyms (1)

RexAB RELATED_SYNONYM · https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md

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 the direct RexAB phage trigger, RexA and RexB molecular coupling, ion-channel activity, lambda self-exclusion control, and sensitive-phage escape routes before minting narrower RexAB mechanism children.

KNOWLEDGE GAP OPEN rexab-mechanism-gap · raised by codex · 2026-09-21

Attached to causal_graphs#rexab_locus_mediates_rex_exclusion

Parma et al. support bacteriophage-lambda rexA and rexB as a two-component system that aborts lytic growth of bacterial viruses, and DefenseFinder maps RexAB to RexAB__RexA and RexAB__RexB profiles. The direct phage trigger, RexA/RexB molecular coupling, ion-channel output, lambda self-exclusion control, and sensitive-phage escape routes remain unresolved.

Curation history

2026-09-21T02:17:07Z · MINTED_TRAITMECH_ID · codex
Minted RexAB 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, history, or prior proposal record; the replacement placeholder is reserved in proposals/metpo_traitmech_v201.
2026-09-21T02:17:08Z · REVIEW_CANONICAL_EXAMPLE_EVIDENCE_GAP · codex
Reviewed canonical example evidence while minting RexAB system and left canonical_examples empty: the bacteriophage-lambda prototype supports a prophage-encoded rexA and rexB exclusion system and the pinned DefenseFinder registry maps a two-profile RexAB namespace, but the available curation sources do not identify a natural organism instance with a directly observed RexAB locus. No paid research was used.