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 A0, A1, and A2. 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.
CITATION STYLE
Milkereit, P., Strauss, D., Bassler, J., Gadal, O., Kühn, H., Schütz, S., … Tschochner, H. (2003). A Noc complex specifically involved in the formation and nuclear export of ribosomal 40 S subunits. Journal of Biological Chemistry, 278(6), 4072–4081. https://doi.org/10.1074/jbc.M208898200
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