Nuclear RanGTP is not required for targeting small nucleolar RNAs to the nucleolus
| Autor: | Anita H. Corbett, Rebecca M. Terns, Julia Eifert, Ian G. Macara, Aarthi Narayanan, Michael P. Terns, Kavita A. Marfatia |
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| Rok vydání: | 2002 |
| Předmět: |
Cytoplasm
Microinjections Nucleolus Xenopus Saccharomyces cerevisiae Active Transport Cell Nucleus Fluorescent Antibody Technique Cell Cycle Proteins Xenopus Proteins Gene Expression Regulation Enzymologic RNA Transport Cell Line Saccharomyces Cricetinae Animals Guanine Nucleotide Exchange Factors RNA Small Nucleolar Small nucleolar RNA Nuclear protein biology urogenital system RNA Nuclear Proteins Cell Biology biology.organism_classification Cell biology Cell Compartmentation Eukaryotic Cells ran GTP-Binding Protein Ran Mutation Oocytes Female Cell Nucleolus |
| Zdroj: | Journal of cell science. 116(Pt 1) |
| ISSN: | 0021-9533 |
| Popis: | The small GTPase Ran is the central regulator of macromolecular transport between the cytoplasm and the nucleus. Recent work has suggested that RanGTP also plays an important role in regulating some intra-nuclear processes. In this study, we have investigated whether RanGTP is required for the intra-nuclear transport of RNAs. Specifically, we directly analyzed the nucleolar localization of Box C/D and Box H/ACA small nucleolar RNAs (snoRNAs)in mammalian (tsBN2) cells, Saccharomyces cerevisiae and Xenopus oocytes under conditions that deplete nuclear RanGTP and prevent RNA export to the cytoplasm. Our data suggest that depletion of nuclear RanGTP does not significantly alter the nucleolar localization of U3 snoRNA in tsBN2 cells. Complementary studies in the budding yeast S. cerevisiae using conditional Ran mutants as well as mutants in Ran regulatory proteins also indicate that disruption of the Ran gradient or of Ran itself does not detectably affect the nucleolar localization of snoRNAs. Finally, microinjection into Xenopus oocytes was used to clearly demonstrate that a specific pool of snoRNAs could still be efficiently targeted to the nucleolus even when the RanGTP gradient was disrupted by microinjection of mutant Ran proteins. Taken together, our data from three phylogenetically distinct experimental systems suggest that nuclear RanGTP,which is essential for trafficking of RNAs between the nuclear and cytoplasmic compartments, is not required for nuclear retention or nucleolar localization of snoRNAs. |
| Databáze: | OpenAIRE |
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