Rrp8p is a yeast nucleolar protein functionally linked to Gar1p and involved in pre-rRNA cleavage at site A2

RNA. 2000 Jun;6(6):826-43. doi: 10.1017/s1355838200992288.


Chemical modifications and processing of the 18S, 5.8S, and 25S ribosomal RNAs from the 35S pre-ribosomal RNA depend on an important set of small nucleolar ribonucleoprotein particles (snoRNPs). Genetic depletion of yeast Gar1p, an essential common component of H/ACA snoRNPs, leads to inhibition of uridine isomerizations to pseudo-uridines on the 35S pre-rRNA and of the early pre-rRNA cleavages at sites A1 and A2, resulting in a loss of mature 18S rRNA synthesis. To identify Gar1p functional partners, we screened for mutations that are synthetically lethal with a gar1 mutant allele encoding a Gar1p mutant protein lacking its two glycine/arginine-rich (GAR) domains. We identified a previously uncharacterized Saccharomyces cerevisiae open reading frame, YDR083W (now designated RRP8), that encodes a highly conserved protein containing motifs found in methyltransferases. Rrp8p localizes to the nucleolus. A yeast strain lacking this protein is viable at 30 degrees C but displays strong growth impairment at lower temperatures. In this strain, cleavage of the pre-rRNA at site A2 is strongly affected whereas cleavages at sites A0 and A1 are only slightly inhibited or delayed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Binding Sites
  • Cloning, Molecular
  • Fungal Proteins / chemistry*
  • Fungal Proteins / genetics
  • Genetic Linkage
  • Hydrolysis
  • Methyltransferases / chemistry
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Mutation
  • Nuclear Proteins / chemistry*
  • Nuclear Proteins / genetics
  • Protein O-Methyltransferase
  • RNA Precursors / chemistry*
  • RNA Precursors / genetics
  • RNA, Small Nucleolar / chemistry*
  • RNA, Small Nucleolar / genetics
  • Ribonucleoproteins, Small Nucleolar*
  • Saccharomyces cerevisiae / chemistry
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / growth & development
  • Saccharomyces cerevisiae Proteins*
  • Sequence Homology, Amino Acid
  • Ultracentrifugation


  • Fungal Proteins
  • Nuclear Proteins
  • RNA Precursors
  • RNA, Small Nucleolar
  • Ribonucleoproteins, Small Nucleolar
  • Saccharomyces cerevisiae Proteins
  • GAR1 protein, S cerevisiae
  • Methyltransferases
  • Protein O-Methyltransferase
  • RRP8 protein, S cerevisiae