Dual roles of the nuclear cap-binding complex and SERRATE in pre-mRNA splicing and microRNA processing in Arabidopsis thaliana
Dual roles of the nuclear cap-binding complex and SERRATE in pre-mRNA splicing and microRNA processing in Arabidopsis thaliana
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DOI：
10.1073/pnas.0802493105
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发表时间：
2008-06-24
影响因子：
11.1
通讯作者：
Weigel, Detlef
中科院分区：
文献类型：
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作者：
Laubinger, Sascha;Sachsenberg, Tirno;Weigel, Detlef
从较长的初级转录本(pri-miRNAs)中加工拟南芥microRNAs(MiRNAs)需要几种蛋白质的活性，包括DICER-like 1(DCL1)、双链RNA结合蛋白HYPONASTIC LEAVES1(HYL1)和锌指蛋白锯齿(SE)。以前已经注意到，弱Se突变体的形态外观使人想起ABH1/CBP80和CBP20突变的植物，这两个突变编码核帽结合复合体的两个亚基。我们报告说，与SE一样，帽结合复合体对于pri-miRNAs的正确处理是必要的。ABH1/CBP80或CBP20的失活会导致成熟miRNAs水平下降，同时Pri-miRNAs明显稳定。全基因组拼接阵列分析表明，Se、abh1/cbp80和cbp20突变体也具有类似的剪接缺陷，导致许多部分剪接转录本的积累。这不太可能是不正确的miRNA加工或其他mRNA周转途径的间接结果，因为保留在se、abh1/cbp80和cbp20突变体中的内含子不受miRNA加工或无义介导的mRNA衰退所需的其他基因突变的影响。综上所述，我们的结果揭示了剪接和miRNA加工中的双重作用，将SE和帽结合复合体与专门的miRNA加工因子如DCL1和HYL1区分开来。
The processing of Arabidopsis thaliana microRNAs (miRNAs) from longer primary transcripts (pri-miRNAs) requires the activity of several proteins, including DICER-LIKE1 (DCL1), the double-stranded RNA-binding protein HYPONASTIC LEAVES1 (HYL1), and the zinc finger protein SERRATE (SE). It has been noted before that the morphological appearance of weak se mutants is reminiscent of plants with mutations in ABH1/CBP80 and CBP20, which encode the two subunits of the nuclear cap-binding complex. We report that, like SE, the cap-binding complex is necessary for proper processing of pri-miRNAs. Inactivation of either ABH1/CBP80 or CBP20 results in decreased levels of mature miRNAs accompanied by apparent stabilization of pri-miRNAs. Whole-genome tiling array analyses reveal that se, abh1/cbp80, and cbp20 mutants also share similar splicing defects, leading to the accumulation of many partially spliced transcripts. This is unlikely to be an indirect consequence of improper miRNA processing or other mRNA turnover pathways, because introns retained in se, abh1/cbp80, and cbp20 mutants are not affected by mutations in other genes required for miRNA processing or for nonsense-mediated mRNA decay. Taken together, our results uncover dual roles in splicing and miRNA processing that distinguish SE and the cap-binding complex from specialized miRNA processing factors such as DCL1 and HYL1.