Nog2p, a putative GTPase associated with pre-60S subunits and required for late 60S maturation steps

Cosmin Saveanu (1) , D. Bienvenu (1) , A. Namane (2) , P. E. Gleizes (3) , Nicole Gas (3) , A. Jacquier (1) , M. Fromont-Racine (1)

1 Génétique des Intéractions Macromoléculaires
2 Protéomique (Plate-Forme)
3 LBME - Laboratoire de biologie moléculaire eucaryote

Eukaryotic ribosome maturation depends on a set of well ordered processing steps. Here we describe the functional characterization of yeast Nog2p (Ynr053cp), a highly conserved nuclear protein. Nog2p contains a putative GTP-binding site, which is essential in vivo. Kinetic and steady-state measurements of the levels of pre-rRNAs in Nog2p-depleted cells showed a defect in 5.8S and 25S maturation and a concomitant increase in the levels of both 27SB(S) and 7S(S) precursors. We found Nog2p physically associated with large pre-60S complexes highly enriched in the 27SB and 7S rRNA precursors. These complexes contained, besides a subset of ribosomal proteins, at least two additional factors, Nog1p, another putative GTP-binding protein, and Rlp24p (Ylr009wp), which belongs to the Rpl24e family of archaeal and eukaryotic ribosomal proteins. In the absence of Nog2p, the pre-60S ribosomal complexes left the nucleolus, but were retained in the nucleoplasm. These results suggest that transient, possibly GTP-dependent association of Nog2p with the pre-ribosomes might trigger late rRNA maturation steps in ribosomal large subunit biogenesis.

Mots clés: Active Transport; Cell Nucleus; Alternative Splicing; Amino Acid Sequence; Binding Sites; Blotting; Northern; Cell Nucleolus; Cytoplasm; DNA; Complementary; Genotype; Glucose; Green Fluorescent Proteins; GTP-Binding Proteins; GTP Phosphohydrolases; Humans; In Situ Hybridization; Kinetics; Luminescent Proteins; Mass Spectrometry; Microscopy; Electron; Fluorescence; Models; Genetic; Molecular Sequence Data; Plasmids; Polyribosomes; Promoter Regions; Protein Binding; Ribosomes; RNA; Messenger; Ribosomal; Sequence Homology; Amino Acid; Time Factors

Domaines: Sciences du Vivant [q-bio]

Cosmin Saveanu, D. Bienvenu, A. Namane, P. E. Gleizes, Nicole Gas, et al.. Nog2p, a putative GTPase associated with pre-60S subunits and required for late 60S maturation steps. EMBO Journal, 2001, 20 (22), pp.6475--6484. ⟨10.1093/emboj/20.22.6475⟩. ⟨pasteur-01404705⟩