Tha system

traitmech:000497 · CLASS · PROPOSED

A phage defense system in which an organism possesses a Tha tail-activated HEPN anti-phage locus that can be activated by incoming-phage minor tail proteins to mediate nonspecific RNase-linked defense.

Trait evidence (5)

DOI:10.1038/s41564-024-01661-6
multiple Staphylococcus aureus prophages encode Tha (tail-activated, HEPN (higher eukaryotes and prokaryotes nucleotide-binding) domain-containing anti-phage system)

Rostol et al. define Tha as a tail-activated HEPN anti-phage system encoded by multiple S. aureus prophages.
DOI:10.1038/s41564-024-01661-6
We demonstrate the function of two Tha systems, Tha-1 and Tha-2, activated by distinct tail proteins

Rostol et al. support multiple experimentally tested Tha variants that are activated by different phage tail proteins.
DOI:10.1038/s41564-024-01661-6
Tha is a non-specific RNase that is activated by conserved minor tail proteins from temperate phages

Rostol et al. connect the Tha anti-phage system to minor-tail-protein activation and nonspecific RNase activity.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md
| Tha | 10\.1038/s41564-024-01661-6 | Bacteriophages avoid autoimmunity from cognate immune systems as an intrinsic part of their life cycles |

The pinned DefenseFinder article registry maps the Tha source key to the primary Nat Microbiol Tha paper.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
| Tha__Tha | | Tha | Custom | 20 |

The pinned DefenseFinder HMM inventory lists one Tha__Tha custom HMM row under the Tha system namespace.

Tha systems activate HEPN RNase defense after tail cues

Conservative system-level sketch linking a Tha locus to incoming-phage minor-tail-protein activation, Tha HEPN RNase activity, and phage-defense-system possession.

NONMECHANISTIC · The graph captures the Tha system at family scope without asserting that all Tha variants sense the same minor tail protein, have the same cognate Ith inhibitor, block the same phages, share the same native prophage organization, or map to a DefenseFinder rules row.

Edge evidence

Tha locus contributes to minor-tail-protein activation RO:0002326
Tha loci encode HEPN anti-phage proteins that can be activated by structural tail proteins of incoming phages.
- DOI:10.1038/s41564-024-01661-6 a defence system activated by structural tail proteins of incoming phages Rostol et al. define Tha as a defense system activated by incoming-phage structural tail proteins.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md | Tha | 10\.1038/s41564-024-01661-6 | Bacteriophages avoid autoimmunity from cognate immune systems as an intrinsic part of their life cycles | The pinned DefenseFinder article registry maps the Tha source key to the primary Nat Microbiol Tha paper.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md | Tha__Tha | | Tha | Custom | 20 | The pinned DefenseFinder HMM inventory lists one Tha__Tha custom HMM row under the Tha system namespace.
minor-tail-protein activation activates Tha HEPN RNase activity RO:0002213
Incoming-phage minor tail proteins activate Tha HEPN-domain RNase activity.
- DOI:10.1038/s41564-024-01661-6 Tha is a non-specific RNase that is activated by conserved minor tail proteins from temperate phages Rostol et al. connect conserved minor tail proteins to Tha RNase activation.
Tha HEPN RNase activity confers Tha system METPO:2007700
Tha-mediated nonspecific RNase activity realizes the Tha system trait.
- DOI:10.1038/s41564-024-01661-6 confirming that Tha-1 is a non-specific RNase Rostol et al. validate Tha-1 nonspecific RNase activity.
Tha system is a phage defense system rdfs:subClassOf
Tha system possession is a phage-defense-system trait.
- DOI:10.1038/s41564-024-01661-6 Tha-1 is an anti-phage system that causes autoimmunity when improperly regulated Rostol et al. experimentally tested the anti-phage properties of Tha-1.

Provenance

Identifier source: TraitMech local identifier
Definition source: DOI:10.1038/s41564-024-01661-6

Parent traits (1)

phage defense system traitmech:000209

Synonyms (3)

Tha EXACT_SYNONYM · DOI:10.1038/s41564-024-01661-6
tail-activated, HEPN domain-containing anti-phage system EXACT_SYNONYM · DOI:10.1038/s41564-024-01661-6
Tha__Tha 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.

Canonical examples (1)

Organisms cited as exemplars of this trait. Taxon ids are NCBITaxon and link out to the NCBI record.

Staphylococcus aureus NCBITaxon:1280 DOI:10.1038/s41564-024-01661-6 Rostol et al. report that multiple Staphylococcus aureus prophages encode Tha and experimentally test Tha-1 and Tha-2 antiphage defense in S. aureus RN4220.

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 Tha variant boundaries, exact minor-tail-protein triggers, Ith inhibitor relationships, native host breadth, and DefenseFinder rule/profile coverage before minting narrower Tha mechanism children.

KNOWLEDGE GAP OPEN tha-variant-profile-rule-gap · raised by codex · 2026-09-30

Attached to causal_graphs#tha_tail_activated_hepn_rnase_defense

Rostol et al. support Tha-1 and Tha-2 as S. aureus prophage-encoded Tha systems activated by distinct incoming-phage minor tail proteins. The pinned DefenseFinder registries map the Tha source key to the same primary paper and list one Tha__Tha custom HMM row, but no exact Tha system rule row was present in the pinned rules table. The first TraitRecord therefore stays at Tha-system scope until separate review resolves variant boundaries, exact activators, Ith inhibitor relationships, native host breadth, and model coverage.

Evidence

DOI:10.1038/s41564-024-01661-6
Tha systems can also block reproduction of the induced tha-positive prophages
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md
| Tha | 10\.1038/s41564-024-01661-6 | Bacteriophages avoid autoimmunity from cognate immune systems as an intrinsic part of their life cycles |
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
| Tha__Tha | | Tha | Custom | 20 |
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv

Curation history

2026-09-30T17:20:02Z · MINTED_TRAITMECH_ID · codex
Minted Tha 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_v374.
2026-09-30T17:20:03Z · REVIEW_CANONICAL_EXAMPLE_EVIDENCE · codex
Reviewed Tha system canonical_examples and kept Staphylococcus aureus because Rostol et al. report that multiple S. aureus prophages encode Tha and experimentally test plasmid-carried Tha-1 and Tha-2 in S. aureus RN4220 phage-challenge assays. No paid research was used.