Functional organization of box C/D RNA-guided RNA methyltransferase

Nucleic Acids Res. 2020 May 21;48(9):5094-5105. doi: 10.1093/nar/gkaa247.


Box C/D RNA protein complexes (RNPs) catalyze site-specific 2'-O-methylation of RNA with specificity determined by guide RNAs. In eukaryotic C/D RNP, the paralogous Nop58 and Nop56 proteins specifically associate with terminal C/D and internal C'/D' motifs of guide RNAs, respectively. We have reconstituted active C/D RNPs with recombinant proteins of the thermophilic yeast Chaetomium thermophilum. Nop58 and Nop56 could not distinguish between the two C/D motifs in the reconstituted enzyme, suggesting that the assembly specificity is imposed by trans-acting factors in vivo. The two C/D motifs are functionally independent and halfmer C/D RNAs can also guide site-specific methylation. Extensive pairing between C/D RNA and substrate is inhibitory to modification for both yeast and archaeal C/D RNPs. N6-methylated adenine at box D/D' interferes with the function of the coupled guide. Our data show that all C/D RNPs share the same functional organization and mechanism of action and provide insight into the assembly specificity of eukaryotic C/D RNPs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenine / analogs & derivatives
  • Chaetomium / genetics
  • Humans
  • Methylation
  • Methyltransferases / chemistry*
  • Methyltransferases / metabolism*
  • Nucleic Acid Conformation
  • RNA / metabolism
  • RNA, Small Nucleolar / chemistry*
  • RNA, Small Nucleolar / metabolism*
  • Ribonucleoproteins / chemistry
  • Ribonucleoproteins / metabolism*
  • Sulfolobus solfataricus


  • RNA, Small Nucleolar
  • Ribonucleoproteins
  • RNA
  • Methyltransferases
  • Adenine
  • 6-methyladenine