SsrA-mediated trans-translation plays a role in mRNA quality control by facilitating degradation of truncated mRNAs

Yasufumi Yamamoto, Takafumi Sunohara, Kaoru Jojima, Toshifumi Inada, Hiroji Aiba

Research output: Contribution to journalArticlepeer-review

88 Citations (Scopus)


An important unsolved question regarding the bacterial SsrA system is the fate of target mRNAs replaced by SsrA RNA during trans-translation. The aim of the present study is to address the potential role of SsrA system in mRNA quality control, focusing on truncated mRNAs that are expected to arise from 3′-to-5′ exonucleolytic attack. We found that significant amounts of truncated mRNAs and polypeptides were produced from genes lacking a ρ-independent terminator in SsrA-deficient cells. These truncated mRNAs, hence truncated polypeptides, were no longer observed in the presence of SsrA RNA. The data indicate that the SsrA system facilitates degradation of "nonstop" mRNAs by presumably removing the stalled ribosomes. Furthermore, analysis of affinity-purified proteins indicated that truncated polypeptides could be produced even from a gene with an intact ρ-independent terminator, although less efficiently, implying that C-terminally truncated proteins and 3κ-truncated mRNA may be produced from virtually all protein-coding genes. We conclude that the SsrA system not only promotes the degradation of incomplete polypeptides but also minimizes the synthesis of incomplete polypeptides by facilitating the degradation of truncated mRNAs that are produced in cells.

Original languageEnglish
Pages (from-to)408-418
Number of pages11
Issue number4
Publication statusPublished - 2003 Apr 1
Externally publishedYes


  • Nonstop mRNA
  • Quality control
  • Trans-translation
  • mRNA degradation
  • tmRNA

ASJC Scopus subject areas

  • Molecular Biology


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