Retrograde nuclear accumulation of cytoplasmic tRNA in rat hepatoma cells in response to amino acid deprivation
| Autor: | Anita K. Hopper, Leonard S. Jefferson, Athulaprabha Murthi, Scot R. Kimball, Hussam H. Shaheen, Rick L. Horetsky |
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| Rok vydání: | 2007 |
| Předmět: |
Carcinoma
Hepatocellular Active Transport Cell Nucleus Biology Cytosol RNA Transfer Transcription (biology) Cell Line Tumor Gene expression medicine Animals Amino Acids In Situ Hybridization Fluorescence Cell Nucleus chemistry.chemical_classification Multidisciplinary Biological Sciences Rats Amino acid Cell nucleus medicine.anatomical_structure Biochemistry chemistry Cytoplasm Transfer RNA Nuclear transport |
| Zdroj: | Proceedings of the National Academy of Sciences. 104:8845-8850 |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.0700765104 |
| Popis: | Until recently, transport of tRNA was presumed to be unidirectional, from the nucleus to the cytoplasm. Our published findings, however, revealed that cytoplasmic tRNAs move retrograde to the nucleus in Saccharomyces cerevisiae and that nuclear accumulation of cytoplasmic tRNAs occurs when cells are nutrient deprived. The findings led us to examine whether retrograde nuclear accumulation of cytoplasmic tRNAs occurs in higher eukaryotes. Using RNA FISH and Northern and Western analyses we show that tRNAs accumulate in nuclei of a hepatoma cell line in response to amino acid deprivation. To discern whether tRNA nuclear accumulation results from nuclear import of cytoplasmic tRNAs, transcription of new RNAs was inhibited, and the location of “old” tRNAs in response to nutrient stress was determined. Even in the absence of new RNA synthesis, there were significant tRNA nuclear pools after amino acid depletion, providing strong evidence that retrograde traffic is responsible for the tRNA nuclear pools. Further analyses showed that retrograde tRNA nuclear accumulation in hepatoma cells is a reversible and energy-dependent process. The data provide evidence for retrograde tRNA nuclear accumulation in intact mammalian cells and support the hypothesis that nuclear accumulation of cytoplasmic tRNA and tRNA re-export to the cytoplasm may constitute a universal mechanism for posttranscriptional regulation of global gene expression in response to nutrient availability. |
| Databáze: | OpenAIRE |
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