n nnnThe eukaryotic nucleolus is multifunctional and involved inthe metabolism and assembly of many different RNAs and ribonucleoproteinparticles as well as in cellular functions, such as cell divisionand transcriptional silencing in plants. We previously showedthat Arabidopsis thaliana exon junction complex proteins associatewith the nucleolus, suggesting a role for the nucleolus in mRNAproduction. Here, we report that the plant nucleolus containsmRNAs, including fully spliced, aberrantly spliced, and singleexon gene transcripts. Aberrant mRNAs are much more abundantin nucleolar fractions, while fully spliced products are moreabundant in nucleoplasmic fractions. The majority of the aberranttranscripts contain premature termination codons and have characteristicsof nonsense-mediated decay (NMD) substrates. A direct link betweenNMD and the nucleolus is shown by increased levels of the sameaberrant transcripts in both the nucleolus and in Up-frameshift(upf) mutants impaired in NMD. In addition, the NMD factorsUPF3 and UPF2 localize to the nucleolus, suggesting that theArabidopsis nucleolus is therefore involved in identifying aberrantmRNAs and NMD.展开▼
机译:ABSTRACTn FONT> TH> TR> TABLE> n
n TOP n <字体颜色= 464c53>抽象 FONT> n 介绍 n 结果 n 讨论 n 方法 n 参考文献 n FONT> TH> TR> TABLE> n nnn,真核细胞核是多功能的,并参与 SUP>元许多不同的RNA和核糖蛋白 SUP>颗粒的代谢和组装以及细胞功能,例如植物的细胞分裂 SUP>和转录沉默。我们先前显示了 SUP>,拟南芥 I>外显子连接复合蛋白将 SUP>与核仁相关,暗示了核仁在mRNA SUP中的作用>生产。在这里,我们报道植物核仁包含 SUP> mRNA,包括完全剪接,异常剪接和单个 SUP>外显子基因转录本。异常的mRNAs在核仁级分中含量丰富得多,而完全剪接的产物在核质级分中含量更高 sup>。大多数异常的 SUP>转录本都含有过早的终止密码子,并且具有无义介导的衰变(NMD)底物的特征 SUP>。 SUP> NMD和核仁之间的直接联系通过核仁和上移框 I> SUP>异常转录本水平的提高来表明> SUP>( upf I>)突变体在NMD中受损。此外,NMD因子 SUP> UPF3和UPF2定位于核仁,这表明 SUP> 拟南芥 I>核仁因此参与了异常 < / SUP> mRNA和NMD。 SUP>
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Genetics Programme, Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, Scotland, United Kingdom;
Department of Cell and Developmental Biology, John Innes Centre, Colney, Norwich NR4 7UH, United Kingdom;
Genetics Programme, Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, Scotland, United Kingdom;
Department of Cell and Developmental Biology, John Innes Centre, Colney, Norwich NR4 7UH, United Kingdom;
Genetics Programme, Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, Scotland, United Kingdom;
Genetics Programme, Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, Scotland, United Kingdom;
Department of Cell and Developmental Biology, John Innes Centre, Colney, Norwich NR4 7UH, United Kingdom;
Genetics Programme, Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, Scotland, United Kingdom|Division of Plant Sciences, University of Dundee at Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, Scotland, United Kingdom;