| First Author | Lapik YR | Year | 2007 |
| Journal | Mol Cell Biol | Volume | 27 |
| Issue | 21 | Pages | 7735-44 |
| PubMed ID | 17785438 | Mgi Jnum | J:129074 |
| Mgi Id | MGI:3768609 | Doi | 10.1128/MCB.01161-07 |
| Citation | Lapik YR, et al. (2007) Restricting conformational flexibility of the switch II region creates a dominant-inhibitory phenotype in Obg GTPase Nog1. Mol Cell Biol 27(21):7735-44 |
| abstractText | Nog1 is a conserved eukaryotic GTPase of the Obg family involved in the biogenesis of 60S ribosomal subunits. Here we report the unique dominant-inhibitory properties of a point mutation in the switch II region of mouse Nog1; this mutation is predicted to restrict conformational mobility of the GTP-binding domain. We show that although the mutation does not significantly affect GTP binding, ectopic expression of the mutant in mouse cells disrupts productive assembly of pre-60S subunits and arrests cell proliferation. The mutant impairs processing of multiple pre-rRNA intermediates, resulting in the degradation of the newly synthesized 5.8S/28S rRNA precursors. Sedimentation analysis of nucleolar preribosomes indicates that defective Nog1 function inhibits the conversion of 32S pre-rRNA-containing complexes to a smaller form, resulting in a drastic accumulation of enlarged pre-60S particles in the nucleolus. These results suggest that conformational changes in the switch II element of Nog1 have a critical importance for the dissociation of preribosome-bound factors during intranucleolar maturation and thereby strongly influence the overall efficiency of the assembly process. |
