Investigation of premature termination codon recognition in nonsense-mediated mRNA decay

Joncourt, Raphael (24 January 2014). Investigation of premature termination codon recognition in nonsense-mediated mRNA decay (Unpublished). In: Swiss RNA Workshop 2014. Bern, Schweiz. 24.01.2014.

Nonsense-mediated mRNA decay (NMD) is best known for its role in quality control of mRNAs, where it recognizes premature translation termination codons (PTCs) and rapidly degrades the corresponding mRNA. The basic mechanism of NMD appears to be conserved among eukaryotes: aberrant translation termination triggers NMD. According to the current working model, correct termination requires the interaction of the ribosome with the poly(A)-binding protein (PABPC1) mediated through the eukaryotic release factors 1 (eRF1) and 3 (eRF3). The model predicts that in the absence of this interaction, the NMD core factor UPF1 binds to eRF3 instead and initiates the events ultimately leading to mRNA degradation. However, the exact mechanism of how the decision between proper and aberrant (i.e. NMD-inducing) translation termination occurs is not yet well understood. We address this question using a tethering approach in which proteins of interest are bound to a reporter transcript into the vicinity of a PTC. Subsequently, the ability of the tethered proteins to inhibit NMD and thus stabilize the reporter transcript is assessed. Our results revealed that the C-terminal domain interacting with eRF3 seems not to be necessary for tethered PABPC1 to suppress NMD. In contrast, the N-terminal part of PABPC1, consisting of 4 RNA recognition motifs (RRMs) and interacting with eukaryotic initiation factor 4G (eIF4G), retains the ability to inhibit NMD. We find that eIF4G is able to inhibit NMD in a similar manner as PABPC1 when tethered to the reporter mRNA. This stabilization by eIF4G depends on two key interactions. One of these interactions is to PABPC1, the other is to eukaryotic initiation factor 3 (eIF3). These results confirm the importance of PABPC1 in inhibiting NMD but additionally reveal a role of translation initiation factors in the distinction between bona fide termination codons and PTCs.

Item Type:

Conference or Workshop Item (Poster)

Division/Institute:

08 Faculty of Science > Departement of Chemistry and Biochemistry

UniBE Contributor:

Joncourt, Raphael

Subjects:

500 Science > 570 Life sciences; biology
500 Science > 540 Chemistry

Language:

English

Submitter:

Christina Schüpbach

Date Deposited:

23 Dec 2014 14:40

Last Modified:

23 Dec 2014 14:40

URI:

https://boris.unibe.ch/id/eprint/61333

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