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Updated: Aug 18, 2026

Assessment of Selective mRNA Translation in Mammalian Cells by Polysome Profiling
Published on: October 28, 2014
Internal ribosome entry segment-mediated translation during apoptosis: the role of IRES-trans-acting factors
K A Spriggs1, M Bushell, S A Mitchell
1School of Pharmacy, University of Nottingham, University Park, Nottingham, UK.
Abstract:
During apoptosis, there is a reduction in translation initiation caused by caspase cleavage of several of the factors required for the cap-dependent scanning mechanism. Under these circumstances, many proteins that are required for apoptosis are instead translated by the alternative method of internal ribosome entry. This mechanism requires the formation of a complex RNA structural element and in the presence of internal ribosome entry segment (IRES)-trans-acting factors (ITAFs), the ribosome is recruited to the RNA. The interactions of several ITAFs with IRESs have been investigated in detail, and several mechanisms of action have been noted, including acting as chaperones, stabilising and remodelling the RNA structure. Structural remodelling by PTB in particular will be discussed, and how this protein is able to facilitate recruitment of the ribosome to several IRESs by causing previously occluded sites to become more accessible.
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