Sequences within a small yeast RNA required for inhibition of internal initiation of translation: interaction with La and other cellular proteins influences its inhibitory activity

Das, S. ; Kenan, D. J. ; Bocskai, D. ; Keene, J. D. ; Dasgupta, A. (1996) Sequences within a small yeast RNA required for inhibition of internal initiation of translation: interaction with La and other cellular proteins influences its inhibitory activity Journal of Virology, 70 (3). pp. 1624-1632. ISSN 0022-538X

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Official URL: http://jvi.asm.org/cgi/content/abstract/70/3/1624

Abstract

We recently reported purification, determination of the nucleotide sequence, and cloning of a 60-nucleotide RNA (I-RNA) from the yeast Saccharomyces cerevisiae which preferentially blocked cap-independent, internal ribosome entry site (IRES)-mediated translation programmed by the poliovirus (PV) 5' untranslated region (UTR). The I-RNA appeared to inhibit IRES-mediated translation by virtue of its ability to bind a 52- kDa polypeptide which interacts with the 5' UTR of viral RNA. We demonstrate here that the HeLa 52-kDa I-RNA-binding protein is immunologically identical to human La autoantigen. Moreover, I-RNA- mediated purified La protein. By using I-RNAs with defined deletions, we have identified sequences of I-RNA required for inhibition of internal initiation of translation. Two smaller fragments of I-RNA (16 and 25 nucleotides) inhibited PV UTR-mediated translation from both monocistronic and bicistronic RNAs. When transfected into HeLa cells, these derivatives of I-RNA inhibited translation of PV RNA. A comparison of protein binding by active and inactive I-RNA mutants demonstrates that in addition to the La protein, three other polypeptides with apparent molecular masses of 80, 70, and 37 kDa may influence the translation-inhibitory activity of I-RNA.

Item Type:Article
Source:Copyright of this article belongs to American Society for Microbiology.
ID Code:8627
Deposited On:28 Oct 2010 11:15
Last Modified:16 May 2016 18:35

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