Toxic component of a type II toxin-antitoxin (TA) system . A sequence-specific, ribosome-dependent mRNA endoribonuclease that inhibits translation during amino acid starvation (the stringent response). In vitro acts by cleaving mRNA with high codon specificity in the ribosomal A site between positions 2 and 3. The stop codon UAG is cleaved at a fast rate while UAA and UGA are cleaved with intermediate and slow rates. In vitro mRNA cleavage can also occur in the ribosomal E site after peptide release from peptidyl- tRNA in the P site as well as on free 30S subunits . In vivo cuts freque [...]

Toxic component of a type II toxin-antitoxin (TA) system. A sequence-specific endoribonuclease it inhibits protein synthesis by cleaving mRNA and inducing bacterial stasis. It is stable, single- strand specific with mRNA cleavage independent of the ribosome, although translation enhances cleavage for some mRNAs . Cleavage occurs at the 5'-end of ACA sequences, yielding a 2',3'-cyclic phosphate and a free 5'-OH, although cleavage can also occur on the 3'-end of the first A Digests 16S rRNA in vivo 43 nts upstream of the C- terminus; this removes the anti-Shine-Dalgarno sequence forming [...]

Toxic component of a type II toxin-antitoxin (TA) system. A probable translation-dependent mRNA interferase. Overexpression causes cessation of cell growth and inhibits cell proliferation via inhibition of translation; this blockage is overcome by subsequent expression of antitoxin HigA. Overexpression causes cleavage of a number of mRNAs in a translation-dependent fashion, suggesting this is an mRNA interferase. mRNA interferases play a role in bacterial persistence to antibiotics; overexpression of this protein induces persisters resistant to ciprofloxacin and ampicillin

Toxic component of a type II toxin-antitoxin (TA) system, first identified by mutations that increase production of persister cells, a fraction of cells that are phenotypic variants not killed by antibiotics, which lead to multidrug tolerance Persistence may be ultimately due to global remodeling of the persister cell's ribosomes . Phosphorylates Glu-tRNA-ligase (AC P04805, gltX, on 'Ser-239') in vivo . Phosphorylation of GltX prevents it from being charged, leading to an increase in uncharged tRNA(Glu). This induces amino acid starvation and the stringent response via RelA/SpoT and in [...]

Toxic component of a type II toxin-antitoxin (TA) system. A translation-dependent mRNA interferase. Overexpression causes cessation of cell growth and inhibits cell proliferation via inhibition of translation; this blockage is overcome by subsequent expression of antitoxin YafN. Overexpression causes cleavage of a number of mRNAs in a ribosome-dependent fashion. YafO binding to the 50S ribosomal subunit in the translation complex induces mRNA cleavage 3' to the region protected by the ribosome; YafO alone is not able to digest mRNA. mRNA interferases play a role in bacterial persistenc [...]

Toxic component of a type II toxin-antitoxin (TA) system. Plays a significant role in the control of biofilm formation and induction of persister cells in the presence of antibiotics. An mRNA interferase which has been reported to be translation-independent . It has also been reported to be translation-dependent . Cleavage has been reported to occur on either side of G in the sequence GCU . Also reported to cleave after C in GC(A/U) sequences . There are only 14 genes in E.coli W3110 (and probably also MG1655) that do not have a GCU sequence and thus are resistant to the mRNA interfera [...]

Toxic component of a type II toxin-antitoxin (TA) system. Its mode of function is controversial; it has been proposed to be an mRNA interferase but also an inhibitor of translation initiation. When overproduced in wild-type cells, inhibits bacterial growth and translation by cleavage of mRNA molecules while it has a weak effect on colony forming ability. Overproduction of Lon protease specifically activates YoeB-dependent mRNA cleavage, leading to lethality. YefM binds to the promoter region of the yefM-yeoB operon to repress transcription, YeoB acts as a corepressor. Also shown in vit [...]

Toxic component of a type II toxin-antitoxin (TA) system. ChpB is a sequence-specific mRNA and (weak) tmRNA endoribonuclease that inhibits protein synthesis and induces bacterial stasis. Cleavage is independent of the ribosome. Cleavage occurs at ACY sequences where Y is not C. The endoribonuclease activity is not as strong as that of MazF. The endoribonuclease activity (a toxin) is inhibited by its labile cognate antitoxin ChpS. Toxicity results when the levels of ChpS decrease in the cell, leading to mRNA degradation. Both ChpS and ChpB probably bind to the promoter region of the chp [...]

Mrna interferase toxin of toxin-antitoxin pair yafq/dinj; Toxic component of a type II toxin-antitoxin (TA) system . A sequence-specific mRNA endoribonuclease that inhibits translation elongation and induces bacterial stasis . Cleavage occurs between the second and third residue of the Lys codon followed by a G or A (5'AAA(G/A)3'), is reading-frame dependent and occurs within the 5' end of most mRNAs . Ribosome-binding confers the sequence specificity and reading frame- dependence . When overexpressed in liquid media YafQ partially inhibits protein synthesis, with a reduction in growth [...]