empty pericarp4 encodes a mitochondrion-targeted pentatricopeptide repeat protein necessary for seed development and plant growth in maize
empty pericarp4 encodes a mitochondrion-targeted pentatricopeptide repeat protein necessary for seed development and plant growth in maize
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DOI：
10.1105/tpc.105.039594
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发表时间：
2007-01-01
期刊：
影响因子：
11.6
通讯作者：
Consonni, Gabriella
中科院分区：
文献类型：
--
作者：
Gutierrez-Marcos, Jose F.;Dal Pra, Mauro;Consonni, Gabriella
五肽重复序列（PPR）家族代表植物中最大的基因家族之一，在拟南芥中注释有> 440个成员。PPR蛋白被认为在细胞器中的转录后过程的调节中具有主要作用。最近的研究表明，拟南芥PPR蛋白在胚胎发生过程中发挥着重要的，非冗余的作用。在这里，我们证明了突变空果皮4（emp 4），玉米（玉米）PPR编码基因，赋予种子致死表型。突变体胚乳严重受损，在营养输入基部胚乳中具有高度不规则的转移细胞分化。从胚胎拯救实验产生的纯合突变体植物的分析表明，emp 4也影响一般植物的生长。emp 4 -1突变被确定在一个活跃的Mutator（Mu）的人口，共分离分析表明，它产生了从Mu 3元件插入。通过反向遗传学方法获得的4个额外的emp 4等位基因的分离提供了emp 4分子克隆的证据。emp 4编码一种新的614个氨基酸的PPR蛋白。EMP 4含有9个35-氨基酸的PPR基序和N-末端的靶向序列肽，这被定位于线粒体的翻译EMP 4-绿色荧光蛋白融合物所证实。分子分析进一步表明，EMP 4是必要的，以调节正确表达的一个小的线粒体转录子在胚乳中。
The pentatricopeptide repeat (PPR) family represents one of the largest gene families in plants, with > 440 members annotated in Arabidopsis thaliana. PPR proteins are thought to have a major role in the regulation of posttranscriptional processes in organelles. Recent studies have shown that Arabidopsis PPR proteins play an essential, nonredundant role during embryogenesis. Here, we demonstrate that mutations in empty pericarp4 (emp4), a maize (Zea mays) PPR-encoding gene, confer a seed-lethal phenotype. Mutant endosperms are severely impaired, with highly irregular differentiation of transfer cells in the nutrient-importing basal endosperm. Analysis of homozygous mutant plants generated from embryo-rescue experiments indicated that emp4 also affects general plant growth. The emp4-1 mutation was identified in an active Mutator ( Mu) population, and cosegregation analysis revealed that it arose from a Mu3 element insertion. Evidence of emp4 molecular cloning was provided by the isolation of four additional emp4 alleles obtained by a reverse genetics approach. emp4 encodes a novel type of PPR protein of 614 amino acids. EMP4 contains nine 35-amino acid PPR motifs and an N-terminal mitochondrion-targeted sequence peptide, which was confirmed by a translational EMP4-green fluorescent protein fusion that localized to mitochondria. Molecular analyses further suggest that EMP4 is necessary to regulate the correct expression of a small subset of mitochondrial transcripts in the endosperm.