Yeast cells are incapable of translating RNAs containing the poliovirus 5' untranslated region: evidence for a translational inhibitor.
AUTOR(ES)
Coward, P
RESUMO
We have expressed in the yeast Saccharomyces cerevisiae a full-length poliovirus cDNA clone under the control of the GAL10 promoter to better characterize the effect of poliovirus on host cell metabolism. We find that yeast cells are unable to translate poliovirus RNA in vivo and that this inhibition is mediated through the 5' untranslated region of the viral RNA. The in vivo inhibition of translation of poliovirus RNA and P2CAT RNA (which contains the 5' untranslated region fused upstream of the bacterial chloramphenicol transferase gene) can be mimicked in vitro in yeast translation lysates. In fact, a trans-acting inhibitor present in yeast lysates can inhibit translation of either poliovirus or P2CAT RNA in HeLa cell translation lysates. In contrast, when the inhibitor is added to translations programmed with chloramphenicol acetyltransferase RNA, yeast prepro-alpha-factor RNA, or an RNA containing the internal ribosome entry site of encephalomyocarditis virus, no inhibition is seen. The inhibitory activity has been partially purified by DEAE-Sephacel chromatography. The partially purified inhibitor is heat stable, escapes phenol extraction, is resistant to proteinase K and DNase I treatment, and is sensitive to RNase A digestion, suggesting that the inhibitor is an RNA. In an in vitro translation assay, the inhibitory activity can be overcome by increasing the concentration of HeLa cell lysate but not P2CAT RNA, suggesting that the inhibitor interacts (directly or indirectly) with one or more components of the HeLa cell translational machinery rather than with the viral RNA.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=238286Documentos Relacionados
- Proteins binding to 5' untranslated region sites: a general mechanism for translational regulation of mRNAs in human and yeast cells.
- 5' untranslated sequences are required for the translational control of a yeast regulatory gene.
- The 5' untranslated sequence of the c-sis/platelet-derived growth factor 2 transcript is a potent translational inhibitor.
- In vitro mutational analysis of cis-acting RNA translational elements within the poliovirus type 2 5' untranslated region.
- Heterogeneity in the 5' untranslated region of mouse cytochrome cT mRNAs leads to altered translational status of the mRNAs.