Mutation of the pentatricopeptide repeat-SMR protein SVR7 impairs accumulation and translation of chloroplast ATP synthase subunits in Arabidopsis thaliana
Mutation of the pentatricopeptide repeat-SMR protein SVR7 impairs accumulation and translation of chloroplast ATP synthase subunits in Arabidopsis thaliana
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DOI：
10.1007/s10265-012-0527-1
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发表时间：
2013-05
影响因子：
2.8
通讯作者：
Reimo Zoschke;Yujiao Qu;Y. Zubo;T. Börner;Christian Schmitz-Linneweber
中科院分区：
文献类型：
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作者：
Reimo Zoschke;Yujiao Qu;Y. Zubo;T. Börner;Christian Schmitz-Linneweber
RNA加工、RNA编辑、RNA剪接和RNA翻译激活是叶绿体基因表达的重要转录后步骤。通常，介导这些过程的因子是核编码的，并在翻译后导入叶绿体。在陆地植物中，大五肽重复（PPR）蛋白家族成员在叶绿体RNA加工的各个步骤中都是必需的。有趣的是，PPR蛋白的一个亚群携带一个c端小的MutS相关（SMR）结构域。在这里，我们分析了拟南芥中编码PPR-SMR蛋白的vr7基因突变的后果。我们证明svr7突变导致叶绿体ATP合酶水平的特异性降低。此外，我们还发现了vr7突变体中ATP合成酶编码mrna的异常转录模式。最后，atpb / eandrbclmrna在vr7突变体中的核糖体关联减少，表明PPR-SMR蛋白SVR7参与了这些mrna的翻译激活。我们描述了SVR7在翻译中的功能相对于其玉米同源物ATP4已经扩展。该结果为该蛋白在真子叶植物和单子叶植物中的功能保守性提供了证据，从而增加了对PPR-SMR蛋白功能和进化的认识。
RNA processing, RNA editing, RNA splicing and translational activation of RNAs are essential post-transcriptional steps in chloroplast gene expression. Typically, the factors mediating those processes are nuclear encoded and post-translationally imported into the chloroplasts. In land plants, members of the large pentatricopeptide repeat (PPR) protein family are required for individual steps in chloroplast RNA processing. Interestingly, a subgroup of PPR proteins carries a C-terminal small MutS related (SMR) domain. Here we analyzed the consequences of mutations in theSVR7gene, which encodes a PPR-SMR protein, inArabidopsis thaliana. We demonstrate thatSVR7mutations lead to a specific reduction in chloroplast ATP synthase levels. Furthermore, we found aberrant transcript patterns for ATP synthase coding mRNAs insvr7mutants. Finally, a reduced ribosome association ofatpB/EandrbcLmRNAs insvr7mutants suggests the involvement of the PPR-SMR protein SVR7 in translational activation of these mRNAs. We describe that the function of SVR7 in translation has expanded relative to its maize ortholog ATP4. The results provide evidence for a relaxed functional conservation of this PPR-SMR protein in eudicotyledonous and monocotyledonous plants, thus adding to the knowledge about the function and evolution of PPR-SMR proteins.