Programmed genetic decoding with an emphasis on translational bypassing

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O'Loughlin, Sinéad
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University College Cork
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The process of gene expression was long believed to be fixed across all domains of life, set in stone by both the universality of the genetic code and the protein-synthesising machinery that decodes it. However, exceptions are known to exist for a minority of mRNAs which temporarily bend the rules of standard decoding. These exceptions can range from a proportion of ribosomes temporarily changing directionality along an mRNA and realigning to an alternative frame, to ribosomes possessing the ability to subvert translation of a block of nucleotides and resume translation downstream on the mRNA transcript. In further cases, ribosomes can redefine the meaning of a stop or sense codon. This assortment of non-canonical translational events is collectively known as Recoding. It can be further subdivided into several respective categories: frameshifting, bypassing, and redefinition. Recoding events are distinct from standard errors in translation due to the programmed fashion in which they occur, with their efficiency tuned by a set of cis-acting elements located 3’ and/or 5’ of the recode site, as well as by trans-acting factors. Translational recoding is in direct competition with standard decoding, facilitating the synthesis of multiple products from the same mRNA transcript, and thus seamlessly adding an extra layer of information to the proteome.
Translation , Recoding , Ribosome , Structure , Bypassing , Frameshifting
O'Loughlin, S. 2020. Programmed genetic decoding with an emphasis on translational bypassing. PhD Thesis, University College Cork.