DRT4 system

traitmech:000546 · CLASS · PROPOSED

A DRT system in which an organism possesses a genome-encoded DefenseFinder DRT_4 subtype locus represented by the DRT_4__drt4 profile.

Trait evidence (6)

DOI:10.1126/science.aba0372
We discovered that a family of uncharacterized reverse transcriptases (RTs) are active defense systems

Gao et al. experimentally support defense-associated reverse transcriptases as active antiphage systems.
DOI:10.1126/science.aba0372
We named these genes defense-associated RTs (DRTs)

Gao et al. coined the defense-associated RT naming that underlies the DRT system family.
DOI:10.1126/science.aba0372
In all cases, mutations in the RT active site [(Y/F)xDD to (Y/F)xAA, where x is any amino acid] abolished activity

Gao et al. connect DRT antiphage activity to conserved reverse-transcriptase active-site residues.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md
| DRT | 10\.1126/science\.aba0372 | Diverse enzymatic activities mediate antiviral immunity in prokaryotes |

The pinned DefenseFinder article registry maps the DRT source key to the Gao et al. prokaryotic antiviral-immunity paper.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
| DRT_4__drt4 | DRT_4__drt4 | DRT_4 | Custom | 350 |

The pinned DefenseFinder HMM inventory records DRT_4__drt4 under the DRT_4 model namespace.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv
DRT DRT_4 1 1 DRT_4__drt4

The pinned DefenseFinder rules table models DRT_4 as a DRT subsystem with a DRT_4__drt4 profile.

DRT4 loci support DRT antiphage defense

Conservative system-level sketch linking a DRT4 locus to reverse-transcriptase-dependent DRT phage defense and DRT4 system possession.

NONMECHANISTIC · The graph captures DRT4 at DefenseFinder subtype-locus level without asserting the direct DRT4 reverse-transcriptase product, phage trigger, native host breadth, sensitive phage breadth, partner-feature requirements, profile-to-activity criteria, or whether every DefenseFinder DRT_4 prediction is a complete experimentally active DRT4 locus.

Edge evidence

DRT4 locus contributes to DRT reverse-transcriptase active-site activity RO:0002326
DRT4 loci are represented in DefenseFinder by a custom defense-associated reverse transcriptase profile.
- DOI:10.1126/science.aba0372 We named these genes defense-associated RTs (DRTs) Gao et al. coined the defense-associated RT naming that underlies the DRT system family.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md | DRT_4__drt4 | DRT_4__drt4 | DRT_4 | Custom | 350 | The pinned DefenseFinder HMM inventory records DRT_4__drt4 under the DRT_4 model namespace.
DRT reverse-transcriptase active-site activity confers DRT4 system METPO:2007700
The first-pass DRT4 system trait is realized by a DefenseFinder DRT_4 subtype locus within the reverse-transcriptase-dependent DRT family.
- DOI:10.1126/science.aba0372 We discovered that a family of uncharacterized reverse transcriptases (RTs) are active defense systems Gao et al. experimentally support defense-associated reverse transcriptases as active antiphage systems.
- DOI:10.1126/science.aba0372 In all cases, mutations in the RT active site [(Y/F)xDD to (Y/F)xAA, where x is any amino acid] abolished activity Gao et al. connect DRT antiphage activity to conserved reverse-transcriptase active-site residues.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv DRT DRT_4 1 1 DRT_4__drt4 The pinned DefenseFinder rules table models DRT_4 as a DRT subsystem with a DRT_4__drt4 profile.
DRT4 system is a DRT system rdfs:subClassOf
DRT4 system possession is a DRT-system trait.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md | DRT | 10\.1126/science\.aba0372 | Diverse enzymatic activities mediate antiviral immunity in prokaryotes | The pinned DefenseFinder article registry maps the DRT source key to the Gao et al. prokaryotic antiviral-immunity paper.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv DRT DRT_4 1 1 DRT_4__drt4 The pinned DefenseFinder rules table models DRT_4 as a DRT subsystem with a DRT_4__drt4 profile.

Provenance

Identifier source: TraitMech local identifier
Definition source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv

Parent traits (1)

DRT system traitmech:000279

Synonyms (2)

DRT_4 RELATED_SYNONYM · https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv
DRT_4__drt4 RELATED_SYNONYM · https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.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 DRT4 reverse-transcriptase product, direct phage trigger, host breadth, partner-feature requirements, and DRT_4 profile-to-activity criteria before minting DRT4 mechanism or component children.

KNOWLEDGE GAP OPEN drt4-profile-activity-gap · raised by codex · 2026-10-02

Attached to causal_graphs#drt4_locus_reverse_transcriptase_defense

Gao et al. support defense-associated reverse transcriptases as a broad antiphage-system family, and the pinned DefenseFinder HMM inventory and rules table support DRT_4 as a single-profile DRT subsystem. This first-pass record leaves the exact DRT4 RT product, phage trigger, host breadth, partner-feature requirements, and profile-to-activity requirements unresolved.

Evidence

DOI:10.1126/science.aba0372
We discovered that a family of uncharacterized reverse transcriptases (RTs) are active defense systems
DOI:10.1126/science.aba0372
In all cases, mutations in the RT active site [(Y/F)xDD to (Y/F)xAA, where x is any amino acid] abolished activity
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
| DRT_4__drt4 | DRT_4__drt4 | DRT_4 | Custom | 350 |
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv
DRT DRT_4 1 1 DRT_4__drt4

Curation history

2026-10-02T13:40:28Z · MINTED_TRAITMECH_ID · codex
Minted DRT4 system as a DOI- and DefenseFinder-backed GENOMICS TraitRecord under the DRT system parent after an ignored-and-hidden duplicate review found no exact live DRT4 TraitMech, METPO, history, or prior proposal record; the replacement placeholder is reserved in proposals/metpo_traitmech_v423.
2026-10-02T13:40:29Z · REVIEW_CANONICAL_EXAMPLE_EVIDENCE_GAP · codex
Reviewed DRT4 system during initial curation and left canonical_examples empty because Gao et al. and the pinned DefenseFinder tables support the DRT family and the DRT_4 model namespace but not an accession-backed native microbial taxon exemplar tied to DRT_4__drt4 and experimentally verified endogenous DRT4 activity. No paid research was used.