RT Journal Article
SR Electronic
T1 Human NMD ensues independently of stable ribosome stalling
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2019.12.11.872861
DO 10.1101/2019.12.11.872861
A1 Evangelos D. Karousis
A1 Lukas-Adrian Gurzeler
A1 Giuditta Annibaldis
A1 René Dreos
A1 Oliver Mühlemann
YR 2019
UL http://biorxiv.org/content/early/2019/12/12/2019.12.11.872861.abstract
AB Nonsense-mediated mRNA decay (NMD) is a translation-dependent RNA degradation pathway that is important for the elimination of faulty and the regulation of normal mRNAs. The molecular details of the early steps in NMD are not fully understood but previous work suggests that NMD activation occurs as a consequence of ribosome stalling at the termination codon (TC). To test this hypothesis, we established an in vitro translation-coupled toeprinting assay based on lysates from human cells that allows monitoring of ribosome occupancy at the TC of reporter mRNAs. In contrast to the prevailing NMD model, our in vitro system revealed similar ribosomal occupancy at the stop codons of NMD-sensitive and NMD-insensitive reporter mRNAs. Moreover, ribosome profiling revealed a similar density of ribosomes at the TC of endogenous NMD-sensitive and NMD-insensitive mRNAs in vivo. Together, these data show that NMD activation is not accompanied by stable stalling of ribosomes at TCs.