Cic1p/Nsa3p is required for synthesis and nuclear export of 60S ribosomal subunits.

Cic1p/Nsa3p was previously reported to be associated with the 26S proteasome and required for the degradation of specific substrates, but was also shown to be associated with early pre-60S particles and to be localized to the nucleolus. Here we report that Cic1p/Nsa3p is required for the synthesis of 60S ribosome subunits. A temperature-sensitive lethal cic1-2 point mutation inhibits synthesis of the mature 5.8S and 25S rRNAs. Release of the pre-60S particles from the nucleolus to the nucleoplasm was also inhibited as judged by the nuclear accumulation of an Rpl11b-GFP reporter construct. We suggest that Cic1p/Nsa3p associates early with nascent preribosomal particles and is required for correct processing and nuclear release of large ribosomal subunit precursors.

Citation

Alessandro Fatica, Marlene Oeffinger, David Tollervey, Irene Bozzoni. Cic1p/Nsa3p is required for synthesis and nuclear export of 60S ribosomal subunits. RNA (New York, N.Y.). 2003 Dec;9(12):1431-6

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PMID: 14623999

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