Viperin system

traitmech:000263 · CLASS · PROPOSED

A phage defense system in which an organism possesses a prokaryotic viperin locus represented by a pVip profile that can produce antiviral modified ribonucleotides and protect against phage infection.

Trait evidence (5)

DOI:10.1038/s41586-020-2762-2
Here we show that eukaryotic viperin originated from a clade of bacterial and archaeal proteins that protect against phage infection

Bernheim et al. support treating prokaryotic viperins as bacterial and archaeal phage-protective proteins rather than only as an animal antiviral factor.
DOI:10.1038/s41586-020-2762-2
Prokaryotic viperins produce a set of modified ribonucleotides

Bernheim et al. support modified ribonucleotide synthesis as a recurring output of prokaryotic viperin proteins.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md
Viperin | 10\.1038/s41586-020-2762-2 | Prokaryotic viperins produce diverse antiviral molecules

The DefenseFinder model registry maps the named Viperin system to the Bernheim et al. prokaryotic viperin paper.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv
Viperin Viperin 1 1 Viperin__pVip

The DefenseFinder rules table models Viperin with a pVip profile.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
Viperin__pVip | Viperin__pVip | Viperin

The DefenseFinder HMM inventory records pVip in the Viperin model namespace.

Prokaryotic viperins produce antiviral ribonucleotides

Conservative system-level sketch linking possession of a prokaryotic viperin locus to modified ribonucleotide production and inhibited phage transcription.

NONMECHANISTIC · The graph captures characterized pVip-mediated modified ribonucleotide production and T7 transcription inhibition without asserting one universal nucleotide product, viral polymerase target, accessory-gene architecture, or phage range across all Viperin loci.

Edge evidence

Viperin locus contributes to modified ribonucleotide production RO:0002326
The Viperin locus encodes a pVip-class radical-SAM enzyme that produces modified ribonucleotides.
- DOI:10.1038/s41586-020-2762-2 Prokaryotic viperins produce a set of modified ribonucleotides Bernheim et al. support modified ribonucleotide production as a pVip output.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv Viperin Viperin 1 1 Viperin__pVip The DefenseFinder rules table supports pVip as the required Viperin system profile.
modified ribonucleotide production enables T7 phage transcription inhibition RO:0002327
Prokaryotic viperin products can inhibit T7 phage polymerase-dependent transcription.
- DOI:10.1038/s41586-020-2762-2 prokaryotic viperins protect against T7 phage infection by inhibiting viral polymerase-dependent transcription Bernheim et al. connect prokaryotic viperin activity to inhibition of T7 transcription.
T7 phage transcription inhibition confers Viperin system METPO:2007700
Inhibition of phage transcription is a source-backed antiviral output that realizes the Viperin system trait.
- DOI:10.1038/s41586-020-2762-2 prokaryotic viperins protect against T7 phage infection by inhibiting viral polymerase-dependent transcription Bernheim et al. support pVip-mediated protection from T7 phage infection.
Viperin system is a phage defense system rdfs:subClassOf
Viperin system possession is a phage-defense-system trait.
- DOI:10.1038/s41586-020-2762-2 Here we show that eukaryotic viperin originated from a clade of bacterial and archaeal proteins that protect against phage infection Bernheim et al. support Viperin as a prokaryotic phage-defense system.

Provenance

Identifier source: TraitMech local identifier
Definition source: DOI:10.1038/s41586-020-2762-2

Parent traits (1)

phage defense system traitmech:000209

Synonyms (2)

Viperin RELATED_SYNONYM · https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md
pVip RELATED_SYNONYM · DOI:10.1038/s41586-020-2762-2

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 Viperin nucleotide products, accessory genes, and phage-target breadth before minting narrower Viperin mechanism children.

KNOWLEDGE GAP OPEN viperin-product-and-subtype-gap · raised by codex · 2026-09-19

Attached to causal_graphs#viperin_modified_ribonucleotides_restrict_phage

Bernheim et al. support prokaryotic viperins as phage-protective producers of modified ribonucleotides, and DefenseFinder models Viperin through the pVip profile, but Viperin-family loci need separate review before TraitMech asserts one universal antiviral nucleotide, polymerase target, or accessory-gene architecture.

Curation history

2026-09-19T03:43:00Z · MINTED_TRAITMECH_ID · codex
Minted Viperin 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_v140.
2026-09-19T03:58:00Z · EDIT · codex
Replaced the Viperin phage-defense-system subclass edge snippet with a Bernheim et al. phage-protection abstract span found by local adversarial review in issue #1037.
2026-09-19T04:06:03Z · EDIT · codex
Aligned the Viperin definition with the bacterial and archaeal prokaryotic scope identified in Claude review issue #1038.