Healing for destruction: tRNA intron degradation in yeast is a two-step cytoplasmic process catalyzed by tRNA ligase Rlg1 and 5'-to-3' exonuclease Xrn1

Genes Dev. 2014 Jul 15;28(14):1556-61. doi: 10.1101/gad.244673.114.


In eukaryotes and archaea, tRNA splicing generates free intron molecules. Although ∼ 600,000 introns are produced per generation in yeast, they are barely detectable in cells, indicating efficient turnover of introns. Through a genome-wide search for genes involved in tRNA biology in yeast, we uncovered the mechanism for intron turnover. This process requires healing of the 5' termini of linear introns by the tRNA ligase Rlg1 and destruction by the cytoplasmic tRNA quality control 5'-to-3' exonuclease Xrn1, which has specificity for RNAs with 5' monophosphate.

Keywords: 5′ to 3′ exonuclease; Rlg1; Xrn1; intron turnover; tRNA ligation; tRNA splicing.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cytoplasm / metabolism*
  • Exoribonucleases / metabolism*
  • Genome, Fungal
  • Introns*
  • Mutation
  • Phosphorylation
  • RNA Ligase (ATP) / genetics
  • RNA Ligase (ATP) / metabolism
  • RNA, Transfer / genetics*
  • RNA, Transfer / metabolism
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Saccharomyces cerevisiae* / genetics
  • Saccharomyces cerevisiae* / metabolism


  • Saccharomyces cerevisiae Proteins
  • RNA, Transfer
  • Exoribonucleases
  • XRN1 protein, S cerevisiae
  • RNA Ligase (ATP)