Dissecting the role of conserved box C/D sRNA sequences in di-sRNP assembly and function

Nucleic Acids Res. 2010 Dec;38(22):8295-305. doi: 10.1093/nar/gkq690. Epub 2010 Aug 6.

Abstract

In all three kingdoms of life, nucleotides in ribosomal RNA (rRNA) are post-transcriptionally modified. One type of chemical modification is 2'-O-ribose methylation, which is, in eukaryotes and archaea, performed by box C/D small ribonucleoproteins (box C/D sRNPs in archaea) and box C/D small nucleolar ribonucleoproteins (box C/D snoRNPs in eukaryotes), respectively. Recently, the first structure of any catalytically active box C/D s(no)RNP determined by electron microscopy and single particle analysis surprisingly demonstrated that they are dimeric RNPs. Mutational analyses of the Nop5 protein interface suggested that di-sRNP formation is also required for the in vitro catalytic activity. We have now analyzed the functional relevance of the second interface, the sRNA interface, within the box C/D di-sRNP. Mutations in conserved sequence elements of the sRNA, which allow sRNP assembly but which severely interfere with the catalytic activity of box C/D sRNPs, prevent formation of the di-sRNP. In addition, we can observe the dimeric box C/D sRNP architecture with a different box C/D sRNP, suggesting that this architecture is conserved. Together, these results provide further support for the functional relevance of the di-sRNP architecture and also provide a structural explanation for the observed defects in catalysis of 2'-O-ribose methylation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Archaeal Proteins / chemistry*
  • Archaeal Proteins / metabolism
  • Base Sequence
  • Conserved Sequence
  • Dimerization
  • Methanococcales / genetics
  • Mutation
  • RNA, Archaeal / chemistry*
  • RNA, Archaeal / metabolism
  • RNA, Small Untranslated / chemistry*
  • RNA, Small Untranslated / metabolism
  • Ribonucleoproteins / chemistry*
  • Ribonucleoproteins / metabolism

Substances

  • Archaeal Proteins
  • RNA, Archaeal
  • RNA, Small Untranslated
  • Ribonucleoproteins