| Summary: | 碩士 === 長庚大學 === 醫學生物技術研究所 === 98 === Infection by picornaviruses often cause protein redistribution; many nuclear proteins are present only in the cytoplasm after viral infection. In eukaryotic cells, the nuclear import pathways are highly regulated and mediated by import receptors. Our previous study found the re-distributions of nuclear proteins, such as heterogeneous nuclear ribonucleoprotein K (hnRNP K), and Far upstream element-binding protein 2 (FBP2); whereas the 64 kDa subunit of cleavage stimulation factor (CstF-64) was retained in the nucleus during enterovirus 71 (EV71) infection. This investigation found that the infection by EV71 or expression of viral 2A protease impaired the function of transportin-2 mediated the transport of another nuclear protein, HuR, into the nucleus. However, protein transport mediated by transportin SR, importin 5, 7, 9, and 11 was unaffected under the same conditions. A GFP- fusion study revealed the nuclear localization signals (NLS) or NLS-domains on nuclear proteins is the important factor to influence the re-distribution of a protein by EV71. In summary, our results indicate that the alternation of nuclear importation occurs only in specific import pathways, which may explain the observation of some nuclear protein re-distribution to cytoplasm but some retained in nucleus upon viral infection.
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