title: Nucleolar protein p120 contains an arginine-rich domain that binds to ribosomal RNA.
abstract: Human proliferation-associated protein p120 has previously been shown to localize to the nucleolus, and several functional domains of p120 have been elucidated. By using a nitrocellulose filter binding assay and a Northwestern blotting procedure this study shows that recombinant p120 binds to an rRNA fragment in vitro with a dissociation constant of 4 nM. The specific RNA-binding region of p120 (residues 1-57) was identified with glutathione S-transferase-fused p120 deletion constructs and Northwestern blotting procedures. This RNA-binding region of p120, which includes the nucleolar localization signal of p120, is similar to the arginine-rich RNA-binding regions found in other RNA-binding proteins such as HIV Rev and Tat. Experiments in vivo with HeLa cell nucleolar extracts showed that p120 was associated with the 60-80S pre-ribosomal particles. This association is disrupted by treatment with either RNase A or buffer of high ionic strength. These results suggest that p120 might be involved in rRNA/ribosome maturation, consistent with the role of the yeast homologue Nop2p in rRNA biogenesis.
authors.affiliation: Department of Pharmacology, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, USA.
authors.forename: W C
authors.initials: WC
authors.lastname: Gustafson
authors.forename: C W
authors.initials: CW
authors.lastname: Taylor
authors.forename: B C
authors.initials: BC
authors.lastname: Valdez
authors.forename: D
authors.initials: D
authors.lastname: Henning
authors.forename: A
authors.initials: A
authors.lastname: Phippard
authors.forename: Y
authors.initials: Y
authors.lastname: Ren
authors.forename: H
authors.initials: H
authors.lastname: Busch
authors.forename: E
authors.initials: E
authors.lastname: Durban
mesh_terms: D000595:Amino Acid Sequence; D001120:Arginine / Q000032:analysis*; D001665:Binding Sites; D001667:Binding, Competitive; D015152:Blotting, Northern; D015153:Blotting, Western; D002466:Cell Nucleolus / Q000737:chemistry; D017353:Gene Deletion; D005982:Glutathione Transferase / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009687:Nuclear Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011498:Protein Precursors / Q000378:metabolism; D012335:RNA, Ribosomal / Q000378:metabolism*; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins / Q000378:metabolism; D012261:Ribonucleoproteins / Q000378:metabolism; D012359:tRNA Methyltransferases
chemical_list: D009687:Nuclear Proteins; D011498:Protein Precursors; D012335:RNA, Ribosomal; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D012261:Ribonucleoproteins; D001120:Arginine; C065028:NOP2 protein, human; D012359:tRNA Methyltransferases; D005982:Glutathione Transferase