Investigation of the role of PNRC2 in nonsense-mediated mRNA decay in human cells

Gkratsou, Asimina; Nicholson, Pamela; Colombo, Martino; Mühlemann, Oliver (7 October 2016). Investigation of the role of PNRC2 in nonsense-mediated mRNA decay in human cells (Unpublished). In: EMBO | EMBL Symposium: The Complex Life of mRNA. EMBL Heidelberg, Germany. 05.-08.10.16.

Nonsense-mediated mRNA decay (NMD) is best known as a eukaryotic surveillance mechanism that targets mRNAs containing premature termination codons (PTCs) for degradation. Extending beyond its mRNA surveillance role, NMD also functions as a translation-dependent post-transcriptional regulator of gene expression affecting 3-10 % of all mRNAs, most of which do not contain a PTC. In mammalian cells the degradation of mRNAs targeted by NMD has been reported to involve both endonucleolytic cleavage mediated by SMG6 and exonucleolytic degradation mediated by the heterodimers SMG5-SMG7 or SMG5-PNRC2, respectively, with PNRC2 providing the link between mRNA surveillance and decapping. In an attempt to further investigate the exonucleolytic pathways of mRNA decay in NMD, we examined the roles of UPF1, SMG5, SMG7 and PNRC2 by employing a combination of functional assays and interaction mapping. Our tethered function assays results reveal that decay of a reporter transcript triggered by UPF1 tethering is dependent on PNRC2 and furthermore that PNRC2 and UPF1 both require the exoribonuclease XRN1 for decay, suggesting that this degradation proceeds by direct decapping followed by 5'-3' exonucleolytic decay. Questioning previous conclusions from tethering assays, tethered UPF1-induced RNA decay occurs independently of SMG6 and SMG5/SMG7. Furthermore, we could not detect the previously reported interaction between SMG5 and PNRC2 and instead find tethered SMG5-induced RNA decay to depend on SMG7 but not PNRC2. Our results indicate a role for PNRC2 and UPF1 in promoting 5'-3' exonucleolytic degradation of mRNAs, independent on the presence of a premature termination codon (PTC) and independent of the SMG5-7 proteins.

Item Type:

Conference or Workshop Item (Poster)

Division/Institute:

08 Faculty of Science > Departement of Chemistry and Biochemistry

Graduate School:

Graduate School for Cellular and Biomedical Sciences (GCB)

UniBE Contributor:

Gkratsou, Asimina; Nicholson, Pamela; Colombo, Martino and Mühlemann, Oliver

Subjects:

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

Language:

English

Submitter:

Christina Schüpbach

Date Deposited:

26 Jan 2017 11:41

Last Modified:

26 Jan 2017 11:41

URI:

https://boris.unibe.ch/id/eprint/93326

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