Nuclear RNA surveillance in Saccharomyces cerevisiae: Trf4p-dependent polyadenylation of nascent hypomethylated tRNA and an aberrant form of 5S rRNA

RNA. 2006 Mar;12(3):508-21. doi: 10.1261/rna.2305406. Epub 2006 Jan 23.


1-Methyladenosine modification at position 58 of tRNA is catalyzed by a two-subunit methyltransferase composed of Trm6p and Trm61p in Saccharomyces cerevisiae. Initiator tRNA (tRNAi(Met)) lacking m1A58 (hypomethylated) is rendered unstable through the cooperative function of the poly(A) polymerases, Trf4p/Trf5p, and the nuclear exosome. We provide evidence that a catalytically active Trf4p poly(A) polymerase is required for polyadenylation of hypomethylated tRNAi(Met) in vivo. DNA sequence analysis of tRNAi(Met) cDNAs and Northern hybridizations of poly(A)+ RNA provide evidence that nascent pre-tRNAi(Met) transcripts are targeted for polyadenylation and degradation. We determined that a mutant U6 snRNA and an aberrant form of 5S rRNA are stabilized in the absence of Trf4p, supporting that Trf4p facilitated RNA surveillance is a global process that stretches beyond hypomethylated tRNAi(Met). We conclude that an array of RNA polymerase III transcripts are targeted for Trf4p/ Trf5p-dependent polyadenylation and turnover to eliminate mutant and variant forms of normally stable RNAs.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Base Sequence
  • Catalytic Domain / genetics
  • DNA, Fungal / genetics
  • DNA-Directed DNA Polymerase / genetics
  • DNA-Directed DNA Polymerase / metabolism*
  • DNA-Directed RNA Polymerases / genetics
  • DNA-Directed RNA Polymerases / metabolism
  • Methylation
  • Mutagenesis, Site-Directed
  • RNA Precursors / chemistry
  • RNA Precursors / genetics
  • RNA Precursors / metabolism
  • RNA Processing, Post-Transcriptional
  • RNA, Fungal / chemistry
  • RNA, Fungal / genetics
  • RNA, Fungal / metabolism*
  • RNA, Ribosomal, 5S / chemistry
  • RNA, Ribosomal, 5S / genetics
  • RNA, Ribosomal, 5S / metabolism*
  • RNA, Small Nuclear / chemistry
  • RNA, Small Nuclear / genetics
  • RNA, Small Nuclear / metabolism
  • RNA, Transfer / chemistry
  • RNA, Transfer / genetics
  • RNA, Transfer / metabolism
  • RNA, Transfer, Met / chemistry
  • RNA, Transfer, Met / genetics
  • RNA, Transfer, Met / metabolism
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*


  • DNA, Fungal
  • RNA Precursors
  • RNA, Fungal
  • RNA, Ribosomal, 5S
  • RNA, Small Nuclear
  • RNA, Transfer, Met
  • Saccharomyces cerevisiae Proteins
  • U6 small nuclear RNA
  • pre-tRNA(Met)
  • RNA, Transfer
  • DNA-Directed RNA Polymerases
  • Trf5 protein, S cerevisiae
  • DNA-Directed DNA Polymerase
  • PAP2 protein, S cerevisiae