A programmed -1 ribosomal frameshift signal can function as a cis-acting mRNA destabilizing element.
Nonsense-mediated mRNA decay (NMD) directs rapid degradation of premature termination codon (PTC)-containing mRNAs, e.g. those containing frameshift mutations. Many viral mRNAs encode polycistronic messages where programmed -1 ribosomal frameshift (-1 PRF) signals direct ribosomes to synthesize polyproteins. A previous study, which identified consensus -1 PRF signals in the yeast genome, found that, in contrast to viruses, the majority of predicted -1 PRF events would direct translating ribosomes to PTCs. Here we tested the hypothesis that a -1 PRF signal can function as a cis-acting mRNA destabilizing element by inserting an L-A viral -1 PRF signal into a PGK1 reporter construct in the 'genomic' orientation. The results show that even low levels of -1 PRF are sufficient to target the reporter mRNA for degradation via the NMD pathway, with half-lives similar to messages containing in-frame PTCs. The demonstration of an inverse correlation between frameshift efficiency and mRNA half-lives suggests that modulation of -1 PRF frequencies can be used to post-transcriptionally regulate gene expression. Analysis of the mRNA decay profiles of the frameshift-signal- containing reporter mRNAs also supports the notion that NMD remains active on mRNAs beyond the 'pioneer round' of translation in yeast.
Plant
Ewan P
EP
Department of Cell Biology and Molecular Genetics, Microbiology Building Room 2135, University of Maryland, College Park, MD 20742, USA.
Wang
Pinger
P
Jacobs
Jonathan L
JL
Dinman
Jonathan D
JD
D018389:Codon, Nonsense / Q000235:genetics; D018965:Frameshifting, Ribosomal / Q000235:genetics*; D005800:Genes, Fungal / Q000235:genetics*; D017930:Genes, Reporter / Q000235:genetics; D006207:Half-Life; D008957:Models, Genetic; D020815:Polyproteins / Q000235:genetics; D020871:RNA Stability; D034443:RNA Transport; D012331:RNA, Fungal / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism*; D038621:Regulatory Sequences, Ribonucleic Acid / Q000235:genetics*; D012270:Ribosomes / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics
D018389:Codon, Nonsense; D020815:Polyproteins; D012331:RNA, Fungal; D012333:RNA, Messenger; D038621:Regulatory Sequences, Ribonucleic Acid; D029701:Saccharomyces cerevisiae Proteins