Cbf5p, the putative pseudouridine synthase of H/ACA-type snoRNPs, can form a complex with Gar1p and Nop10p in absence of Nhp2p and box H/ACA snoRNAs

RNA. 2004 Nov;10(11):1704-12. doi: 10.1261/rna.7770604. Epub 2004 Sep 23.


Box C/D and box H/ACA small ribonucleoprotein particles (sRNPs) are found from archaea to humans, and some of these play key roles during the biogenesis of ribosomes or components of the splicing apparatus. The protein composition of the core of both types of particles is well established and the assembly pathway of box C/D sRNPs has been extensively investigated both in archaeal and eukaryotic systems. In contrast, knowledge concerning the mode of assembly and final structure of box H/ACA sRNPs is much more limited. In the present study, we have investigated the protein/protein interactions taking place between the four protein components of yeast box H/ACA small nucleolar RNPs (snoRNPs), Cbf5p, Gar1p, Nhp2p, and Nop10p. We provide evidence that Cbf5p, Gar1p, and Nop10p can form a complex devoid of Nhp2p and small nucleolar RNA (snoRNA) components of the particles and that Cbf5p and Nop10p can directly bind to each other. We also show that the absence of any component necessary for assembly of box H/ACA snoRNPs inhibits accumulation of Cbf5p, Gar1p, or Nop10p, whereas Nhp2p levels are little affected.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Western
  • Dose-Response Relationship, Drug
  • Fungal Proteins / chemistry
  • Fungal Proteins / drug effects
  • Fungal Proteins / metabolism*
  • Hydro-Lyases / metabolism*
  • Magnesium Chloride / pharmacology
  • Microtubule-Associated Proteins / metabolism*
  • Nuclear Proteins / metabolism*
  • Potassium Chloride / pharmacology
  • Protein Structure, Tertiary
  • RNA Precursors / metabolism
  • RNA Processing, Post-Transcriptional
  • RNA-Binding Proteins / metabolism*
  • Recombinant Proteins / metabolism
  • Ribonucleoproteins, Small Nuclear / metabolism*
  • Ribonucleoproteins, Small Nucleolar / metabolism*
  • Saccharomyces cerevisiae / growth & development
  • Saccharomyces cerevisiae Proteins / metabolism*


  • Fungal Proteins
  • Microtubule-Associated Proteins
  • NOP10 protein, S cerevisiae
  • Nuclear Proteins
  • RNA Precursors
  • RNA-Binding Proteins
  • Recombinant Proteins
  • Ribonucleoproteins, Small Nuclear
  • Ribonucleoproteins, Small Nucleolar
  • Saccharomyces cerevisiae Proteins
  • Magnesium Chloride
  • NHP2 protein, S cerevisiae
  • GAR1 protein, S cerevisiae
  • Potassium Chloride
  • Hydro-Lyases
  • CBF5 protein, S cerevisiae
  • pseudouridylate synthetase