Exclusive interaction of the 15.5 kD protein with the terminal box C/D motif of a methylation guide snoRNP

Chem Biol. 2002 Oct;9(10):1095-107. doi: 10.1016/s1074-5521(02)00239-9.


Box C/D small nucleolar RNAs (snoRNAs) direct site-specific methylation of ribose 2'-hydroxyls in ribosomal and spliceosomal RNAs. To identify snoRNA functional groups contributing to assembly of an active box C/D snoRNP in Xenopus oocytes, we developed an in vivo nucleotide analog interference mapping procedure. Deleterious substitutions consistent with requirements for binding the 15.5 kD protein clustered within the terminal box C/D motif only. In vitro analyses confirmed a single interaction site for recombinant 15.5 kD protein and identified the exocyclic amine of A89 in box D as essential for binding. Our results argue that the 15.5 kD protein interacts asymmetrically with the two sets of conserved box C/D elements and that its binding is primarily responsible for the stability of box C/D snoRNAs in vivo.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenosine / analogs & derivatives
  • Adenosine / metabolism
  • Animals
  • Base Sequence
  • Conserved Sequence
  • Methylation
  • Models, Molecular
  • Molecular Sequence Data
  • Molecular Weight
  • Nucleic Acid Conformation
  • Oocytes
  • Protein Binding
  • RNA, Small Nucleolar / chemistry
  • RNA, Small Nucleolar / genetics
  • RNA, Small Nucleolar / metabolism*
  • RNA-Binding Proteins / chemistry
  • RNA-Binding Proteins / metabolism*
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Ribonucleoproteins, Small Nuclear / chemistry
  • Ribonucleoproteins, Small Nuclear / metabolism*
  • Thionucleotides / chemistry
  • Thionucleotides / metabolism
  • Xenopus / metabolism


  • RNA, Small Nucleolar
  • RNA-Binding Proteins
  • Recombinant Proteins
  • Ribonucleoproteins, Small Nuclear
  • Thionucleotides
  • Adenosine