The DExH box protein Suv3p is a component of a yeast mitochondrial 3'-to-5' exoribonuclease that suppresses group I intron toxicity

Cell. 1996 Jan 26;84(2):199-209. doi: 10.1016/s0092-8674(00)80975-7.

Abstract

The yeast mitochondrial protein Suv3p is a putative NTP-dependent RNA helicase. Here we report that in cells lacking Suv3p, there is an approximately 50-fold increase in the excised form of the group I intron omega of the mitochondrial 31S rRNA gene. Surprisingly, little mature 21S rRNA accumulates in those cells; instead, unligated 21S rRNA exons appear. Intron overaccumulation could lead to spliced exon reopening via a reaction known to be catalyzed by group I introns in vitro. We also show that Suv3p is a functional component of a novel mitochondrial NTP-dependent 3'-to-5' exoribonuclease activity that can degrade group I intron RNAs. These findings account for group I intron overaccumulation in cells lacking Suv3p and define a novel function for putative RNA helicases in direct RNA degradation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Base Sequence
  • DEAD-box RNA Helicases
  • DNA, Fungal / analysis
  • Exons / genetics
  • Exoribonucleases / isolation & purification
  • Exoribonucleases / metabolism*
  • Fungal Proteins / genetics
  • Fungal Proteins / isolation & purification
  • Fungal Proteins / metabolism*
  • Introns* / genetics
  • Mitochondria / enzymology*
  • Molecular Sequence Data
  • RNA / metabolism
  • RNA Helicases
  • RNA Nucleotidyltransferases / isolation & purification
  • RNA Nucleotidyltransferases / metabolism*
  • RNA Splicing / physiology*
  • RNA, Fungal / analysis
  • RNA, Fungal / biosynthesis
  • RNA, Fungal / metabolism
  • RNA, Mitochondrial
  • RNA, Ribosomal / biosynthesis
  • RNA, Ribosomal / metabolism
  • Recombinant Fusion Proteins / biosynthesis
  • Recombinant Fusion Proteins / isolation & purification
  • Saccharomyces cerevisiae / enzymology
  • Saccharomyces cerevisiae Proteins*

Substances

  • DNA, Fungal
  • Fungal Proteins
  • RNA, Fungal
  • RNA, Mitochondrial
  • RNA, Ribosomal
  • Recombinant Fusion Proteins
  • Saccharomyces cerevisiae Proteins
  • RNA
  • RNA Nucleotidyltransferases
  • Exoribonucleases
  • SUV3 protein, S cerevisiae
  • DEAD-box RNA Helicases
  • RNA Helicases