The mitochondrion-targeted PENTATRICOPEPTIDE REPEAT78 protein is required for nad5 mature mRNA stability and seed development in maize
The mitochondrion-targeted PENTATRICOPEPTIDE REPEAT78 protein is required for nad5 mature mRNA stability and seed development in maize
复制标题
玉米中 nad5 成熟 mRNA 稳定性和种子发育需要线粒体靶向五肽 REPEAT78 蛋白
DOI：
10.1016/j.molp.2017.09.009
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发表时间：
2017
期刊：
影响因子：
27.5
通讯作者：
Tan Bao-Cai
中科院分区：
文献类型：
--
作者：
Zhang Ya-Feng;Suzuki Masaharu;Sun Feng;Tan Bao-Cai
五肽重复序列(PPR)蛋白是一个RNA结合蛋白家族，参与植物细胞器中的RNA代谢。虽然已经对许多PPR蛋白进行了功能研究，但很少有PPR蛋白与线粒体RNA的稳定性有关。通过反向遗传方法，我们研究了线粒体靶向的PPR78蛋白在玉米(Zea Mays)种子发育和成熟的mRNA稳定性中的作用。PPR78功能的丧失导致线粒体nad5成熟mRNA的稳态水平显著降低，阻断了电子传递链中复合体I的组装，导致胚胎发生和胚乳发育停滞。第二个强等位基因的鉴定证实了PPR78 innad5mRNA积累和玉米种子发育的功能。成熟蛋白5的产生需要三个不同的前体RNA通过RNA剪接反应组装，而在ppr78突变体中nad5T1前体的积累减少。然而，是成熟密码子5的不稳定而不是annad5T1导致了全长nad5转录本的丢失，并且nad5的降解同时丢失了翻译起始密码子和终止密码子。我们的数据表明，成熟蛋白5mRNA的组装先于PPR78的保护作用。
Pentatricopepetide repeat (PPR) proteins are a large family of RNA-binding proteins involved in RNA metabolism in plant organelles. Although many PPR proteins have been functionally studied, few of them are identified with a function in mitochondrial RNA stability. By using a reverse genetic approach, we characterized the role of the mitochondrion-targeted PPR78 protein innad5mature mRNA stability and maize (Zea mays) seed development. Loss of PPR78 function leads to a dramatic reduction in the steady-state level of mitochondrialnad5mature mRNA, blocks the assembly of complex I in the electron transport chain, and causes an arrest in embryogenesis and endosperm development. Characterization of a second strong allele confirms the function of PPR78 innad5mRNA accumulation and maize seed development. The generation of maturenad5requires the assembly of three distinct precursor RNAs viatrans-splicing reactions, and the accumulation ofnad5T1 precursor is reduced in theppr78mutants. However, it is the instability of maturenad5rather thannad5T1 causing loss of the full-lengthnad5transcript, and degradation ofnad5losing both translation start and stop codons is enriched in the mutant. Our data imply the assembly of maturenad5mRNA precedes the protection of PPR78.