Abstract
The SSU processome constitutes a large ribonucleoprotein complex involved in the early steps of ribosome biogenesis. UTP-B is one of the first multi-subunit protein complexes that associates with the pre-ribosomal RNA to form the SSU processome. To understand the molecular basis of the hierarchical assembly of the SSU-processome, we have undergone a structural and functional analysis of the UTP-B subunit Pwp2p. We show that Pwp2p is required for the proper assembly of UTP-B and for a productive association of UTP-B with pre-rRNA. These two functions are mediated by two distinct structural domains. The N-terminal domain of Pwp2p folds into a tandem WD-repeat (tWD) that associates with Utp21p, Utp18p, and Utp6p to form a core complex. The CTDs of Pwp2p and Utp21p mediate the assembly of the heterodimer Utp12p:Utp13p that is required for the stable incorporation of the UTP-B complex in the SSU processome. Finally, we provide evidence suggesting a role of UTP-B as a platform for the binding of assembly factors during the maturation of 20S rRNA precursors.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Binding Sites
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Cloning, Molecular
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Escherichia coli / genetics
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Escherichia coli / metabolism
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Gene Expression
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Gene Expression Regulation, Fungal*
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Nuclear Proteins / chemistry
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism
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Organelle Biogenesis
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Phosphorylation
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Protein Binding
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Protein Conformation, alpha-Helical
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Protein Conformation, beta-Strand
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Protein Interaction Domains and Motifs
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Protein Multimerization
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RNA Precursors / genetics
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RNA Precursors / metabolism
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RNA, Ribosomal / genetics*
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RNA, Ribosomal / metabolism
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RNA-Binding Proteins / chemistry
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RNA-Binding Proteins / genetics
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RNA-Binding Proteins / metabolism
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Recombinant Proteins / chemistry
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Recombinant Proteins / genetics
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Recombinant Proteins / metabolism
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Ribosomal Proteins / chemistry*
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Ribosomal Proteins / genetics
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Ribosomal Proteins / metabolism
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Ribosomes / genetics*
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Ribosomes / metabolism
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Saccharomyces cerevisiae / genetics*
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Saccharomyces cerevisiae / metabolism
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Saccharomyces cerevisiae Proteins / chemistry*
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Saccharomyces cerevisiae Proteins / genetics
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Saccharomyces cerevisiae Proteins / metabolism
Substances
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Nuclear Proteins
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PWP2 protein, S cerevisiae
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RNA Precursors
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RNA, Ribosomal
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RNA-Binding Proteins
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Recombinant Proteins
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Ribosomal Proteins
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Saccharomyces cerevisiae Proteins
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Utp12 protein, S cerevisiae
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Utp13 protein, S cerevisiae
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Utp18 protein, S cerevisiae
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Utp21 protein, S cerevisiae
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Utp6 protein, S cerevisiae