MazEF system

traitmech:000345 · CLASS · PROPOSED

A phage defense system in which an organism possesses a two-component MazEF toxin-antitoxin locus whose MazE antitoxin and MazF endoribonuclease can protect Escherichia coli against RNA phages and that DefenseFinder represents with mandatory MazEF__MazE and MazEF__MazF profiles.

Trait evidence (9)

PMID:40494395
we investigated the role of a model toxin-antitoxin system, MazEF, in protecting Escherichia coli against two RNA phage species

Nikolic et al. directly tested MazEF as an Escherichia coli toxin-antitoxin module protecting against RNA phages.
PMID:40494395
the native presence of mazEF moderately reduced population susceptibility and increased the survival of individual E. coli cells

Nikolic et al. support native mazEF as a moderate RNA phage defense determinant in Escherichia coli.
PMID:40494395
Genomic analysis further revealed an underrepresentation of the MazF cleavage site in genomes of RNA phages infecting E. coli

Nikolic et al. support selection against MazF ACA cleavage sites in RNA phages that infect E. coli.
https://pmc.ncbi.nlm.nih.gov/articles/PMC12151602/
MazEF interferes with RNA phage replication within already infected cells

Nikolic et al. interpret the mazEF deletion phenotype as intracellular interference with RNA phage replication, not an adsorption defect.
https://pmc.ncbi.nlm.nih.gov/articles/PMC12151602/
direct interference, rather than abortive infection, plays the predominant role in the case of MazEF

Nikolic et al. caution that the main MazEF effect in their RNA phage assays appears to be direct interference rather than abortive infection.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md
MazEF | 10\.1098/rsbl\.2025\.0080 | A bacterial toxin-antitoxin system as a native defence element against RNA phages

The DefenseFinder article registry maps the named MazEF system to the Nikolic et al. RNA-phage defense paper.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv
MazEF MazEF 2 2 MazEF__MazE, MazEF__MazF

The DefenseFinder rules table models MazEF as a two-profile system requiring MazE and MazF profiles.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
| MazEF__MazE | MazEF__MazE | MazEF | Custom | 20 |

The DefenseFinder HMM inventory records the MazE profile in the MazEF model namespace.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
| MazEF__MazF | MazEF__MazF | MazEF | Custom | 20 |

The DefenseFinder HMM inventory records the MazF profile in the MazEF model namespace.

MazEF loci reduce RNA phage susceptibility

Conservative system-level sketch linking a MazEF locus to native RNA phage defense and the MazEF system possession trait.

NONMECHANISTIC · The graph captures native MazEF protection against RNA phages without asserting a phage-triggered MazF activation route, a resolved direct phage-RNA cleavage event, MazEF-mediated DNA-phage defense breadth, or a generic abortive-infection output.

Edge evidence

MazEF locus contributes to RNA phage replication interference RO:0002326
Native mazEF contributes to reduced Escherichia coli susceptibility to the MS2 and Qbeta RNA phages.
- PMID:40494395 the native presence of mazEF moderately reduced population susceptibility Nikolic et al. connect native mazEF presence to reduced RNA phage susceptibility.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC12151602/ MazEF interferes with RNA phage replication within already infected cells Nikolic et al. distinguish MazEF-mediated intracellular interference from blocked RNA phage adsorption.
RNA phage replication interference confers MazEF system METPO:2007700
MazEF-associated reduction of RNA phage susceptibility realizes the MazEF system trait.
- PMID:40494395 RNA-degrading toxin-antitoxin systems may also help defend against RNA phages Nikolic et al. frame the MazEF result as support for RNA-degrading toxin-antitoxin systems as RNA phage defense elements.
MazEF system is a phage defense system rdfs:subClassOf
MazEF system possession is a phage-defense-system trait.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md MazEF | 10\.1098/rsbl\.2025\.0080 | A bacterial toxin-antitoxin system as a native defence element against RNA phages DefenseFinder associates MazEF with the Nikolic et al. RNA-phage defense paper.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv MazEF MazEF 2 2 MazEF__MazE, MazEF__MazF The DefenseFinder rules table models MazEF as a two-profile system requiring MazE and MazF profiles.

Provenance

Identifier source: TraitMech local identifier
Definition source: DOI:10.1098/rsbl.2025.0080

Parent traits (1)

phage defense system traitmech:000209

Synonyms (4)

MazEF EXACT_SYNONYM · PMID:40494395
mazEF RELATED_SYNONYM · PMID:40494395
MazEF__MazE RELATED_SYNONYM · https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
MazEF__MazF 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.

Escherichia coli NCBITaxon:562 DOI:10.1098/rsbl.2025.0080 Nikolic et al. compared Escherichia coli K-12 MG1655 derivatives carrying or lacking the native mazEF locus and found moderate but measurable native mazEF protection against the MS2 and Qbeta RNA phages.

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 MazEF activation, direct MazF RNA targets, and RNA- versus DNA-phage breadth before minting narrower MazEF mechanism children.

KNOWLEDGE GAP OPEN mazef-activation-breadth-gap · raised by codex · 2026-09-21

Attached to causal_graphs#mazef_rna_phage_defense

Nikolic et al. support native MazEF protection against RNA phages and argue that direct interference predominates in those assays, but the phage-induced route to active MazF, the relative contributions of phage-RNA cleavage and host-RNA degradation, the breadth of MazEF DNA-phage defense, and the DefenseFinder MazEF model boundaries remain unresolved.

Curation history

2026-09-21T21:03:46Z · MINTED_TRAITMECH_ID · codex
Minted MazEF 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_v222.