DRT system

traitmech:000279 · CLASS · PROPOSED

A phage defense system in which an organism possesses a defense-associated reverse transcriptase locus whose RT-domain component or components can confer bacteriophage defense and are modeled by DefenseFinder as DRT subtypes.

Trait evidence (8)

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

Gao et al. experimentally support previously uncharacterized reverse transcriptases as active antiphage defense systems rather than mobile-element RT features alone.
DOI:10.1126/science.aba0372
six of these candidates (UG1, UG2, UG3, UG8, UG15, and UG16) provided robust protection against dsDNA phages

Gao et al. support DRT defense activity across several reverse-transcriptase candidate groups.
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 label.
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.
DOI:10.1126/science.aba0372
the UG3 (drt3a) and UG8 (drt3b) RTs are components of the same defense system (DRT type 3), with both RTs required for defense activity

Gao et al. support the multi-component DRT type 3 system while separating it from single-gene DRT subtypes.
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 DefenseFinder article registry maps the named DRT system to the Gao et al. antiphage-system discovery paper.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv
DRT DRT_1 2 2 DRT_1__drt1a, DRT_1__drt1b

The DefenseFinder rules table models DRT_1 as a two-profile DRT subtype.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
DRT_1__drt1a | DRT_1__drt1a | DRT_1

The DefenseFinder HMM inventory records the drt1a profile in the DRT_1 model namespace.

DRT loci use reverse transcriptases for antiphage defense

Conservative system-level sketch linking a DRT locus to reverse-transcriptase active-site dependence, subtype-specific bacteriophage resistance, and the DRT system trait.

NONMECHANISTIC · The graph captures DRT systems at the family level while leaving the direct RT products, phage triggers, subtype-specific partner proteins or non-coding RNAs, additional subtype mechanisms, and exact phage targets unresolved.

Edge evidence

DRT locus contributes to defense-associated RT activity RO:0002326
DRT loci encode defense-associated RT-domain proteins.
- DOI:10.1126/science.aba0372 We named these genes defense-associated RTs (DRTs) Gao et al. connect the DRT name to reverse-transcriptase defense genes.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md DRT_1__drt1a | DRT_1__drt1a | DRT_1 DefenseFinder includes drt1a in the custom DRT_1 model profile inventory.
defense-associated RT activity contributes to subtype-specific phage resistance RO:0002326
Conserved reverse-transcriptase active-site residues are required for DRT-mediated defense activity.
- 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. show DRT antiphage activity requires RT active-site residues.
DRT locus contributes to subtype-specific phage resistance RO:0002326
Experimentally reconstructed DRT candidate systems provide protection against dsDNA phages.
- DOI:10.1126/science.aba0372 six of these candidates (UG1, UG2, UG3, UG8, UG15, and UG16) provided robust protection against dsDNA phages Gao et al. support DRT loci as defensive against bacteriophages in heterologous reconstruction assays.
- DOI:10.1126/science.aba0372 the UG3 (drt3a) and UG8 (drt3b) RTs are components of the same defense system (DRT type 3), with both RTs required for defense activity Gao et al. support multi-component DRT type 3 as one DRT-system subtype.
subtype-specific phage resistance confers DRT system METPO:2007700
DefenseFinder models DRT as a phage-defense system with subtype models such as DRT_1.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv DRT DRT_1 2 2 DRT_1__drt1a, DRT_1__drt1b The DefenseFinder rules table supports DRT_1 as a named defense-system subtype model with drt1a and drt1b profiles.
DRT system is a phage defense system rdfs:subClassOf
DRT system possession is a phage-defense-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 DefenseFinder associates DRT with the Gao et al. prokaryotic antiviral-immunity paper.

Provenance

Identifier source: TraitMech local identifier
Definition source: DOI:10.1126/science.aba0372

Parent traits (1)

phage defense system traitmech:000209

Children (9)

Synonyms (3)

DRT EXACT_SYNONYM · https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md
defense-associated RT RELATED_SYNONYM · DOI:10.1126/science.aba0372
defense-associated reverse transcriptase RELATED_SYNONYM · DOI:10.1126/science.aba0372

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 DRT subtype products, partner RNAs or proteins, phage triggers, and antiphage substrates before minting narrower DRT subtype mechanism children.

KNOWLEDGE GAP OPEN drt-subtype-mechanism-gap · raised by codex · 2026-09-19

Attached to causal_graphs#drt_reverse_transcriptase_antiphage_defense

Gao et al. support several active reverse-transcriptase-containing antiphage systems, and DefenseFinder models DRT subtypes such as DRT_1. This first record stays at DRT-family level because the direct products of DRT RT activity, the exact phage triggers, the non-coding RNA role in DRT type 3, and the mechanisms for additional DRT subtypes are not resolved.

Curation history

2026-09-19T12:30:14Z · MINTED_TRAITMECH_ID · codex
Minted DRT system as a DOI-backed GENOMICS TraitRecord under phage defense system after an ignored-and-hidden duplicate review found no exact live TraitMech, METPO, or prior proposal record; the replacement placeholder is reserved in proposals/metpo_traitmech_v156.