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Comparative and Functional Genomics
Volume 2012, Article ID 391546, 12 pages
http://dx.doi.org/10.1155/2012/391546
Review Article

Alternative Mechanisms to Initiate Translation in Eukaryotic mRNAs

Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Nicolás Cabrera, 1, Cantoblanco, 28049 Madrid, Spain

Received 4 November 2011; Accepted 20 January 2012

Academic Editor: Greco Hernández

Copyright © 2012 Encarnación Martínez-Salas et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The composition of the cellular proteome is under the control of multiple processes, one of the most important being translation initiation. The majority of eukaryotic cellular mRNAs initiates translation by the cap-dependent or scanning mode of translation initiation, a mechanism that depends on the recognition of the m7G(5)ppp(5)N, known as the cap. However, mRNAs encoding proteins required for cell survival under stress bypass conditions inhibitory to cap-dependent translation; these mRNAs often harbor internal ribosome entry site (IRES) elements in their 5UTRs that mediate internal initiation of translation. This mechanism is also exploited by mRNAs expressed from the genome of viruses infecting eukaryotic cells. In this paper we discuss recent advances in understanding alternative ways to initiate translation across eukaryotic organisms.