Mechanism of tmRNA-mediated trans-translation

点击翻译按钮获取中文摘要

1) Ribosome stalling by the rare codon induces mRNA cleavage, resulting in nonstop mRNAs that are recognized by tmRNA.2) Ribosome stalling at the cognate stop codon caused by reduced activity or expression of RF-1 or RF-2 induces mRNA cleavage, resulting in nonstop mRNAs that are recognized by tmRNA.3) Ribosome stalling caused by amino acid starvation induces mRNA cleavage at the corresponding codons, resulting in nonstop mRNAs that are recognized by tmRNA.4)The ribosome-mediated mRNA cleavage along with the tmRNA system is an important mechanism that enables cells to adapt to amino acid starvation conditions.5) Trans-translation occurs at the A-site of the ribosome without cleavage of mRNA, and that compeptition among tRNA, tmRNARF and RRF occurs at the A-site.6) SmpB binds not only the tRNA domain but also the mRNA domain of tmRNA to determine the initiation point of tag-translation.7) In vitro trans-translation system was developed using purified translation factors. Using this system, we revealed that trans-translation does not require S 1 protein.8) We have proposed new concepts, "a protein mimicking tRNA+mRNA" and "a protein encoding an amino acid".