Both introns and long 3'-UTRs operate as cis-acting elements to trigger nonsense-mediated decay in plants.
Nonsense-mediated mRNA decay (NMD) is a eukaryotic quality control mechanism that identifies and eliminates aberrant mRNAs containing a premature termination codon (PTC). Although, key trans-acting NMD factors, UPF1, UPF2 and UPF3 are conserved in yeast and mammals, the cis-acting NMD elements are different. In yeast, short specific sequences or long 3'-untranslated regions (3'-UTRs) render an mRNA subject to NMD, while in mammals' 3'-UTR located introns trigger NMD. Plants also possess an NMD system, although little is known about how it functions. We have elaborated an agroinfiltration-based transient NMD assay system and defined the cis-acting elements that mediate plant NMD. We show that unusually long 3'-UTRs or the presence of introns in the 3'-UTR can subject mRNAs to NMD. These data suggest that both long 3'-UTR-based and intron-based PTC definition operated in the common ancestors of extant eukaryotes (stem eukaryotes) and support the theory that intron-based NMD facilitated the spreading of introns in stem eukaryotes. We have also identified plant UPF1 and showed that tethering of UPF1 to either the 5'- or 3'-UTR of an mRNA results in reduced transcript accumulation. Thus, plant UPF1 might bind to mRNA in a late, irreversible phase of NMD.
Kertész
Sándor
S
Agricultural Biotechnology Center, Gödöllo, Hungary.
Kerényi
Zoltán
Z
Mérai
Zsuzsanna
Z
Bartos
Imre
I
Pálfy
Tamás
T
Barta
Endre
E
Silhavy
Dániel
D
D020413:3' Untranslated Regions / Q000737:chemistry*; D020121:5' Untranslated Regions / Q000737:chemistry; D017360:Arabidopsis / Q000235:genetics; D029681:Arabidopsis Proteins / Q000502:physiology; D018389:Codon, Nonsense; D018506:Gene Expression Regulation, Plant; D007438:Introns; D020365:RNA Helicases / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism*; D038621:Regulatory Sequences, Ribonucleic Acid; D012231:Rhizobium / Q000235:genetics
D020413:3' Untranslated Regions; D020121:5' Untranslated Regions; D029681:Arabidopsis Proteins; D018389:Codon, Nonsense; D012333:RNA, Messenger; D038621:Regulatory Sequences, Ribonucleic Acid; C513125:UPF1 protein, Arabidopsis; D020365:RNA Helicases