title: Final pre-40S maturation depends on the functional integrity of the 60S subunit ribosomal protein L3.
abstract: Ribosomal protein L3 is an evolutionarily conserved protein that participates in the assembly of early pre-60S particles. We report that the rpl3[W255C] allele, which affects the affinity and function of translation elongation factors, impairs cytoplasmic maturation of 20S pre-rRNA. This was not seen for other mutations in or depletion of L3 or other 60S ribosomal proteins. Surprisingly, pre-40S particles containing 20S pre-rRNA form translation-competent 80S ribosomes, and translation inhibition partially suppresses 20S pre-rRNA accumulation. The GTP-dependent translation initiation factor Fun12 (yeast eIF5B) shows similar in vivo binding to ribosomal particles from wild-type and rpl3[W255C] cells. However, the GTPase activity of eIF5B failed to stimulate processing of 20S pre-rRNA when assayed with ribosomal particles purified from rpl3[W255C] cells. We conclude that L3 plays an important role in the function of eIF5B in stimulating 3' end processing of 18S rRNA in the context of 80S ribosomes that have not yet engaged in translation. These findings indicate that the correct conformation of the GTPase activation region is assessed in a quality control step during maturation of cytoplasmic pre-ribosomal particles.
authors.affiliation: Departamento de Genética, Universidad de Sevilla, and Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.
authors.forename: Juan J
authors.initials: JJ
authors.lastname: García-Gómez
authors.affiliation: Departamento de Genética, Universidad de Sevilla, and Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Fernández-Pevida
authors.affiliation: Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom.
authors.forename: Simon
authors.initials: S
authors.lastname: Lebaron
authors.affiliation: Departamento de Genética, Universidad de Sevilla, and Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.
authors.forename: Iván V
authors.initials: IV
authors.lastname: Rosado
authors.affiliation: Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom.
authors.forename: David
authors.initials: D
authors.lastname: Tollervey
authors.affiliation: Unit of Biochemistry, Department of Biology, University of Fribourg, Fribourg, Switzerland.
authors.forename: Dieter
authors.initials: D
authors.lastname: Kressler
authors.affiliation: Departamento de Genética, Universidad de Sevilla, and Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.
authors.forename: Jesús
authors.initials: J
authors.lastname: de la Cruz
mesh_terms: D000483:Alleles; D003593:Cytoplasm / Q000235:genetics / Q000378:metabolism; D039642:Eukaryotic Initiation Factors / Q000235:genetics; D009154:Mutation; D046988:Proteasome Endopeptidase Complex / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D012322:RNA Precursors / Q000235:genetics; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D000090822:Ribosomal Protein L3; D012269:Ribosomal Proteins / Q000235:genetics* / Q000378:metabolism; D054683:Ribosome Subunits, Large, Eukaryotic / Q000235:genetics* / Q000378:metabolism; D054682:Ribosome Subunits, Small, Eukaryotic / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics*
chemical_list: D039642:Eukaryotic Initiation Factors; D012322:RNA Precursors; D012337:RNA, Ribosomal, 18S; D000090822:Ribosomal Protein L3; D012269:Ribosomal Proteins; C451459:eukaryotic initiation factor-5B; D046988:Proteasome Endopeptidase Complex