Single-molecule visualization of mRNA circularization during translation

Abstract

Translation is mediated by precisely orchestrated sequential interactions among translation initiation components, mRNA, and ribosomes. Biochemical, structural, and genetic techniques have revealed the fundamental mechanism that determines what occurs and when, where and in what order. Most mRNAs are circularized via the eIF4E–eIF4G–PABP interaction, which stabilizes mRNAs and enhances translation by recycling ribosomes. However, studies using single-molecule fluorescence imaging have allowed for the visualization of complex data that opposes the traditional “functional circularization” theory. Here, we briefly introduce single-molecule techniques applied to studies on mRNA circularization and describe the results of in vitro and live-cell imaging. Finally, we discuss relevant insights and questions gained from single-molecule research related to translation.

Functions of RNA-Binding Proteins in Cardiovascular Disease

“…The circularization promotes the recycling of post-termination ribosomes for translation reinitiation. Cytoplasmic regulation of the length of the poly(A) tail is thus a highly efficient mechanism to regulate mRNA translation [9].…”

Recruitment of the 40S ribosomal subunit by the West Nile virus 3′ UTR promotes the cross-talk between the viral genomic ends for translation regulation

“…Cyclization is required for the recruitment of the NS5 polymerase during the initiation of the minus strand RNA synthesis ( Davis et al, 2013 ; Dong et al, 2008 ; Filomatori et al, 2006 ; Liu et al, 2016 ; Meyer et al, 2020 ; Zhang et al, 2008 ), while it interferes with efficient translation initiation by affecting the folding of those structural elements required for the proper ribosome scanning, e.g., cHP ( Funk et al, 2010 ; Manzano et al, 2011 ; Sztuba-Solinska et al, 2013 ; Xing et al, 2021 ). Nevertheless, the acquisition of a circular conformation by cellular eukaryotic mRNAs is a mainstream requisite for protein synthesis initiation ( Kim et al, 2023 ). Therefore, if a circular genomic conformation was required for translation in WNV, alternative mechanisms to the establishment of direct RNA-RNA interactions should trigger the acquisition of such conformation.…”