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 Article (Journal Article)

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.

Full Text

Duke Authors

Cited Authors

  • Das, S; Kenan, DJ; Bocskai, D; Keene, JD; Dasgupta, A

Published Date

  • March 1996

Published In

Volume / Issue

  • 70 / 3

Start / End Page

  • 1624 - 1632

PubMed ID

  • 8627683

Pubmed Central ID

  • PMC189986

International Standard Serial Number (ISSN)

  • 0022-538X

Digital Object Identifier (DOI)

  • 10.1128/JVI.70.3.1624-1632.1996


  • eng

Conference Location

  • United States