Human proliferation-associated protein p120 has previously been shown to localize to the nucleolus, and several functional domains of p120 have been elucidated. By using a nitrocellulose filter binding assay and a Northwestern blotting procedure this study shows that recombinant p120 binds to an rRNA fragment in vitro with a dissociation constant of 4 nM. The specific RNA-binding region of p120 (residues 1–57) was identified with glutathione S-transferase-fused p120 deletion constructs and Northwestern blotting procedures. This RNA-binding region of p120, which includes the nucleolar localization signal of p120, is similar to the arginine-rich RNA-binding regions found in other RNA-binding proteins such as HIV Rev and Tat. Experiments in vivo with HeLa cell nucleolar extracts showed that p120 was associated with the 60–80 S pre-ribosomal particles. This association is disrupted by treatment with either RNase A or buffer of high ionic strength. These results suggest that p120 might be involved in rRNA/ribosome maturation, consistent with the role of the yeast homologue Nop2p in rRNA biogenesis.
Nucleolar protein p120 contains an arginine-rich domain that binds to ribosomal RNA
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W. Clay GUSTAFSON, Charles W. TAYLOR, Benigno C. VALDEZ, Dale HENNING, Alba PHIPPARD, Young REN, Harris BUSCH, Egon DURBAN; Nucleolar protein p120 contains an arginine-rich domain that binds to ribosomal RNA. Biochem J 15 April 1998; 331 (2): 387–393. doi: https://doi.org/10.1042/bj3310387
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