The Arabidopsis U12-Type Spliceosomal Protein U11/U12-31K Is Involved in U12 Intron Splicing via RNA Chaperone Activity and Affects Plant Development
The Arabidopsis U12-Type Spliceosomal Protein U11/U12-31K Is Involved in U12 Intron Splicing via RNA Chaperone Activity and Affects Plant Development
复制标题
DOI：
10.1105/tpc.110.079103
复制
发表时间：
2010-12-01
期刊：
影响因子：
11.6
通讯作者：
Kang, Hunseung
中科院分区：
文献类型：
--
作者：
Kim, Won Yong;Jung, Hyun Ju;Kang, Hunseung
U12内含子通过含有U11和U12小核核糖核蛋白的U12内含子特异性剪接体从前体mrna中去除。虽然已经鉴定了几种u12型剪接体特有的蛋白质，但它们影响u12依赖性内含子剪接以及植物生长发育的方式仍然很大程度上未知。在这里，我们评估了u12型剪接体蛋白U11/U12-31K在拟南芥中的作用。未获得t - dna标记的U11/U12-31K纯合子系，杂合子突变体在种子成熟过程中存在缺陷，表明U11/U12-31K对拟南芥的正常发育至关重要。人工microRNA敲低U11/U12- 31k，导致U12内含子正常剪接缺陷，导致拟南芥茎生长发育异常。这种剪接缺陷并不局限于特定的U12型内含子，但大多数U12内含子剪接受到U11/U12- 31k的影响。外源施用赤霉素（GA）可以恢复生长迟缓的花序茎，但细胞分裂素、生长素或油菜素内酯不能恢复生长。在U11/U12-31K基因敲低的植物中，GA代谢相关基因高度下调。重要的是，U11/U12-31K被确定具有RNA伴侣活性。我们认为U11/U12- 31k是一种RNA伴侣蛋白，它是U12内含子正确剪接和植物正常生长发育所必需的。
U12 introns are removed from precursor-mRNA by a U12 intron-specific spliceosome that contains U11 and U12 small nuclear ribonucleoproteins. Although several proteins unique to the U12-type spliceosome have been identified, the manner by which they affect U12-dependent intron splicing as well as plant growth and development remain largely unknown. Here, we assessed the role of U11/U12-31K, a U12-type spliceosomal protein in Arabidopsis thaliana. T-DNA-tagged homozygote lines for U11/U12-31K could not be obtained, and heterozygote mutants were defective for seed maturation, indicating that U11/U12-31K is essential for the normal development of Arabidopsis. Knockdown of U11/U12-31K by artificial microRNA caused a defect in proper U12 intron splicing, resulting in abnormal stem growth and development of Arabidopsis. This defect in proper splicing was not restricted to specific U12-type introns, but most U12 intron splicing was influenced by U11/U12-31K. The stunted inflorescence stem growth was recovered by exogenously applied gibberellic acid (GA), but not by cytokinin, auxin, or brassinosteroid. GA metabolism-related genes were highly downregulated in U11/U12-31K knockdown plants. Importantly, U11/U12-31K was determined to harbor RNA chaperone activity. We propose that U11/U12-31K is an RNA chapereone that is indispensible for proper U12 intron splicing and for normal growth and development of plants.