title: A common core RNP structure shared between the small nucleoar box C/D RNPs and the spliceosomal U4 snRNP.
abstract: The box C/D snoRNAs function in directing 2'-O-methylation and/or as chaperones in the processing of ribosomal RNA. We show here that Snu13p (15.5 kD in human), a component of the U4/U6.U5 tri-snRNP, is also associated with the box C/D snoRNAs. Indeed, genetic depletion of Snu13p in yeast leads to a major defect in RNA metabolism. The box C/D motif can be folded into a stem-internal loop-stem structure, almost identical to the 15.5 kD binding site in the U4 snRNA. Consistent with this, the box C/D motif binds Snu13p/ 15.5 kD in vitro. The similarities in structure and function observed between the U4 snRNP (chaperone for U6) and the box C/D snoRNPs raises the interesting possibility that these particles may have evolved from a common ancestral RNP.
authors.affiliation: Max-Planck-Institut für Biophysikalische Chemie, Abteilung Zelluläre Biochemie, Göttingen, Germany.
authors.forename: N J
authors.initials: NJ
authors.lastname: Watkins
authors.forename: V
authors.initials: V
authors.lastname: Ségault
authors.forename: B
authors.initials: B
authors.lastname: Charpentier
authors.forename: S
authors.initials: S
authors.lastname: Nottrott
authors.forename: P
authors.initials: P
authors.lastname: Fabrizio
authors.forename: A
authors.initials: A
authors.lastname: Bachi
authors.forename: M
authors.initials: M
authors.lastname: Wilm
authors.forename: M
authors.initials: M
authors.lastname: Rosbash
authors.forename: C
authors.initials: C
authors.lastname: Branlant
authors.forename: R
authors.initials: R
authors.lastname: Lührmann
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D019143:Evolution, Molecular; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D006367:HeLa Cells; D006801:Humans; D008970:Molecular Weight; D009690:Nucleic Acid Conformation; D011233:Precipitin Tests; D011485:Protein Binding; D012331:RNA, Fungal / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012342:RNA, Small Nuclear / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020537:RNA, Small Nucleolar / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D017414:Ribonucleoprotein, U4-U6 Small Nuclear / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D020718:Ribonucleoproteins, Small Nucleolar / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D017381:Spliceosomes / Q000737:chemistry* / Q000235:genetics; D013379:Substrate Specificity; D015003:Yeasts / Q000235:genetics / Q000378:metabolism*
chemical_list: D005656:Fungal Proteins; D012331:RNA, Fungal; D012342:RNA, Small Nuclear; D020537:RNA, Small Nucleolar; C117378:RNA, U3 small nucleolar; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; D017414:Ribonucleoprotein, U4-U6 Small Nuclear; D020718:Ribonucleoproteins, Small Nucleolar; C405482:U4 small nuclear RNA; C117377:ribonucleoprotein, U3 small nucleolar