Evasion of bacteria-mediated translation shutoff by virus (kw:KW-1259)

Viral infections disturb the host physiological balance and can trigger host antiviral defense systems. Some of these defense systems alter vital cellular processes by blocking a crucial step of virus multiplication and ending up with the host cell dormancy or even death .
The blockage is mediated by host proteins, designed here as toxins, that are activated upon infection. The vast majority of toxins found so far interfere with the translation process, mostly via mRNA or tRNA cleavage .
Some of these toxins are part of a toxin-antitoxin system (TA) where the toxin is normally kept inactive by the antitoxin. Some toxins have been named Abi (abortive infection) according to the fatal outcome .
Prokaryotic viruses can counteract these defense systems by making up for the altered function or by mimicking the antitoxin molecule in order to protect themselves against the negative effects of toxin activation.

Here are some examples of viruses counteracting the host translational shutoff:

Family Genus Virus Host bacteria Bacterial toxin Toxin activation Toxin activity Viral evasion strategy Ref.
Myoviridae unclassified ΦTE Pectobacterium atrosepticum ToxN Degradation of antitoxin ToxI mRNAs site-specific endoribonuclease Viral pseudo-ToxI RNA
Myoviridae Punalikevirus Enterobacteria phage P1 E.coli MazF Degradation of antitoxin MazE mRNAs site-specific endoribonuclease ?
Myoviridae T4likevirus Enterobacteria phage T4 E.coli RnlA Degradation of antitoxin RnlB mRNAs endoribonuclease Viral antitoxin Dmd
Myoviridae T4likevirus Enterobacteria phage T4 E.coli LsoA Degradation of antitoxin LsoB mRNAs endoribonuclease Viral antitoxin Dmd
Myoviridae T4likevirus Enterobacteria phage T4 E.coli PrrC By T4 Stp tRNALys anticodon nuclease T4 polynucleotide kinase or RNA ligase repair enzymes
Myoviridae T4likevirus Enterobacteria phage T4 E.coli LitA Complex of T4 Gol and host EF-Tu Host EF-Tu cleavage Mutations in Gol
Siphoviridae unclassified Lactococcus phage P008 L.lactis AbiQ Degradation of antitoxin mRNA Endoribonuclease gp38 mediated?

Matching UniProtKB/Swiss-Prot entries

(all links/actions below point to uniprot.org website)

4 entries grouped by strain

3 entries

Enterobacteria phage T4 (Bacteriophage T4) reference strain

RLIG_BPT4 RNA ligase 1 (EC (Gene product 63) (gp63) (Rnl1)
KIPN_BPT4 Polynucleotide kinase (PNK) (EC (Deoxynucleotide 3'-phosphatase) (EC ...
DMD_BPT4 Antitoxin Dmd

1 entry

Rhodothermus phage RM378 (Bacteriophage RM378)

RLIG_BPRHR RNA ligase (EC 6.5.1.-)