Abstract
It has been reported that eukaryotic organisms have so-called nonsense-mediated mRNA decay (NMD) system. NMD is an RNA surveillance pathway that degrades mRNAs with nonsense mutation, thus avoiding production of possibly toxic truncated proteins. Three interacting proteins, UPF1, UPF2 and UPF3, are required for NMD in mammals and yeasts including plants.
In this study,Arabidopsis sequence database was searched for NMD target mRNAs. We selected five of these mRNAs and checked for the presence of nonsense mutation in these mRNAs. As a result we identified at least two mRNA variants with or without nonsense mutation produced by alternative splicing for each gene. We analyzed stability of mRNAs with nonsense mutation in wild-type and upf3 mutant plants. These mRNAs with nonsense mutation were unstable in wild-type plants than in upf3 mutant plants. This indicated that the UPF3 gene is required by the plant NMD system to obviate aberrantly spliced mRNA.
