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Spb1p is a putative methyltransferase required for 60S ribosomal subunit biogenesis in Saccharomyces cerevisiae

Kressler, Dieter ; Rojo, Manuel ; Linder, Patrick ; de la Cruz, Jesús

In: Nucleic Acids Research, 1999, vol. 27, no. 23, p. 4598-4608

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    Titre
    • Spb1p is a putative methyltransferase required for 60S ribosomal subunit biogenesis in Saccharomyces cerevisiae
    Auteur
    • Kressler, Dieter. Département de Biochimie Médicale, Centre Médical Universitaire, Université de Genève, 1 rue Michel-Servet, 1211 Genève 4, Switzerland, 47 boulevard de l'Hôpital, 75651 Paris Cedex 13, France
    • Rojo, Manuel. INSERM U523-lnstitut de Myologie, Groupe Hospitalier Pitié-Salpêtrière, 47 boulevard de l'Hôpital, 75651 Paris Cedex 13, France
    • Linder, Patrick. Département de Biochimie Médicale, Centre Médical Universitaire, Université de Genève, 1 rue Michel-Servet, 1211 Genève 4, Switzerland, 47 boulevard de l'Hôpital, 75651 Paris Cedex 13, France
    • de la Cruz, Jesús. Département de Biochimie Médicale, Centre Médical Universitaire, Université de Genève, 1 rue Michel-Servet, 1211 Genève 4, Switzerland, 47 boulevard de l'Hôpital, 75651 Paris Cedex 13, France
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Nucleic Acids Research, 1999, vol. 27, no. 23, p. 4598-4608. Oxford University Press
    Autre version électronique
    Classification
    • Santé
    Identifiant OAI-PMH
    • oai:doc.rero.ch:299322
    Summary
    Several mutants (spb1-spb7) have been previously identified as cold-sensitive extragenic suppressors of loss-of-function mutations in the poly(A)+-binding protein 1 of Saccharomyces cerevisiae. Cloning, sequence and disruption analyses revealed that SPB1 (YCL054W) encodes an essential putative S-adenosyl-methionine-dependent methyltransferase. Polysome analyses showed an under-accumulation of 60S ribosomal subunits in the spb1-1 mutant and in a strain genetically depleted of Spb1p. Northern and primer extension analyses indicated that this was due to inhibition of processing of the 27SB precursors, which results in depletion of the mature 25S and 5.8S rRNAs. At later time points of Spb1p depletion, the stability of 40S ribosomal subunits is also affected. These results suggest that Spb1p is involved in 60S ribosomal subunit biogenesis and associates early with the pre-ribosomes. Consistent with this, hemag-glutinin epitope-tagged Spb1p localizes to the nucleus with nucleolar enrichment. Despite the expected methyltransferase activity of Spb1 p, global methylation of pre-rRNA is not affected upon Spb1p depletion. We propose that Spb1p is required for proper assembly of pre-ribosomal particles during the biogenesis of 60S ribosomal subunits