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Cap- and IRES-independent scanning mechanism of translation initiation as an alternative to the concept of cellular IRESs

Molecules and Cells volume 30, pages 285–293 (2010)Cite this article

Abstract

During the last decade the concept of cellular IRES-elements has become predominant to explain the continued expression of specific proteins in eukaryotic cells under conditions when the cap-dependent translation initiation is inhibited. However, many cellular IRESs regarded as cornerstones of the concept, have been compromised by several recent works using a number of modern techniques. This review analyzes the sources of artifacts associated with identification of IRESs and describes a set of control experiments, which should be performed before concluding that a 5’ UTR of eukaryotic mRNA does contain an IRES. Hallmarks of true IRES-elements as exemplified by well-documented IRESs of viral origin are presented. Analysis of existing reports allows us to conclude that there is a constant confusion of the cap-independent with the IRES-directed translation initiation. In fact, these two modes of translation initiation are not synonymous. We discuss here not numerous reports pointing to the existence of a cap- and IRES-independent scanning mechanism of translation initiation based on utilization of special RNA structures called cap-independent translational enhancers (CITE). We describe this mechanism and suggest it as an alternative to the concept of cellular IRESs.

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  1. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia

    Ivan N. Shatsky, Sergey E. Dmitriev, Ilya M. Terenin & D.E. Andreev

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  1. Ivan N. Shatsky
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  2. Sergey E. Dmitriev
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  3. Ilya M. Terenin
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  4. D.E. Andreev
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Correspondence to Ivan N. Shatsky.

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Shatsky, I.N., Dmitriev, S.E., Terenin, I.M. et al. Cap- and IRES-independent scanning mechanism of translation initiation as an alternative to the concept of cellular IRESs. Mol Cells 30, 285–293 (2010). https://doi.org/10.1007/s10059-010-0149-1

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  • DOI: https://doi.org/10.1007/s10059-010-0149-1

Keywords

  • 5’ CITE
  • 5’ UTRs
  • cap-dependent and cap-independent translation mechanisms
  • IRES elements
  • mammalian mRNAs
  • translation initiation