title: A Noc complex specifically involved in the formation and nuclear export of ribosomal 40 S subunits.
abstract: Formation and nuclear export of 60 S pre-ribosomes requires many factors including the heterodimeric Noc1-Noc2 and Noc2-Noc3 complexes. Here, we report another Noc complex with a specific role in 40 S subunit biogenesis. This complex consists of Noc4p, which exhibits the conserved Noc domain and is homologous to Noc1p, and Nop14p, a nucleolar protein with a role in 40 S subunit formation. Moreover, noc4 thermosensitive mutants are defective in 40 S biogenesis, and rRNA processing is inhibited at early cleavage sites A(0), A(1), and A(2). Using a fluorescence-based visual assay for 40 S subunit export, we observe a strong nucleolar accumulation of the Rps2p-green fluorescent protein reporter in noc4 ts mutants, but 60 S subunit export was normal. Thus, Noc4p and Nop14p form a novel Noc complex with a specific role in nucleolar 40 S subunit formation and subsequent export to the cytoplasm.
authors.affiliation: Biochemie-Zentrum Heidelberg, Im Neuenheimer Feld 328, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Milkereit
authors.forename: Daniela
authors.initials: D
authors.lastname: Strauss
authors.forename: Jochen
authors.initials: J
authors.lastname: Bassler
authors.forename: Olivier
authors.initials: O
authors.lastname: Gadal
authors.forename: Holger
authors.initials: H
authors.lastname: Kühn
authors.forename: Sylvia
authors.initials: S
authors.lastname: Schütz
authors.forename: Nicole
authors.initials: N
authors.lastname: Gas
authors.forename: Johannes
authors.initials: J
authors.lastname: Lechner
authors.forename: Ed
authors.initials: E
authors.lastname: Hurt
authors.forename: Herbert
authors.initials: H
authors.lastname: Tschochner
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism*; D002846:Chromatography, Affinity; D017931:DNA Primers; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
chemical_list: D017931:DNA Primers; C472292:Noc4 protein, S cerevisiae; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins