A Noc complex specifically involved in the formation and nuclear export of ribosomal 40 S subunits.
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.
Mesh Terms:
Amino Acid Sequence, Base Sequence, Cell Nucleus, Chromatography, Affinity, DNA Primers, Molecular Sequence Data, Nuclear Proteins, Plasmids, Protein Transport, Recombinant Fusion Proteins, Ribosomes, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Sequence Homology, Amino Acid
Amino Acid Sequence, Base Sequence, Cell Nucleus, Chromatography, Affinity, DNA Primers, Molecular Sequence Data, Nuclear Proteins, Plasmids, Protein Transport, Recombinant Fusion Proteins, Ribosomes, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Sequence Homology, Amino Acid
J. Biol. Chem.
Date: Feb. 07, 2003
PubMed ID: 12446671
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