Maize Dek44 Encodes Mitochondrial Ribosomal Protein L9 and Is Required for Seed Development
Maize Dek44 Encodes Mitochondrial Ribosomal Protein L9 and Is Required for Seed Development
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玉米 Dek44 编码线粒体核糖体蛋白 L9，是种子发育所必需的
DOI：
10.1104/pp.19.00546
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发表时间：
2019-08-01
期刊：
影响因子：
7.4
通讯作者：
Song, Rentao
中科院分区：
文献类型：
--
作者：
Qi, Weiwei;Lu, Lei;Song, Rentao
线粒体呼吸依赖于由核和线粒体基因组编码的蛋白质。许多呼吸链相关蛋白由线粒体基因组编码，并通过线粒体核糖体进行翻译。新鉴定的玉米（Zea mays）缺陷型kernel 44（dek 44）突变体产生显示胚胎致死表型的小籽粒。我们通过分离产生突变的Mutator标签克隆了Dek 44，并将其鉴定为编码推定的50 S核糖体蛋白L9。超离心亚细胞分离证实DEK 44是一种线粒体核糖体蛋白。DEK 44在单子叶植物中高度保守，仅在籽粒中积累。转录组和逆转录定量PCR分析显示，DEK 44功能的丧失影响编码线粒体和核基因组呼吸链相关蛋白的基因的表达。蓝色的天然PAGE显示显着减少组装的呼吸链复合物dek 44突变体的内核。透射电镜观察表明，dek 44突变体籽粒中线粒体的生物发生和形态受到强烈影响。此外，DEK 44可能通过细胞周期蛋白/细胞周期蛋白依赖性激酶介导的活动来调节细胞生长和籽粒发育。本研究提供了深入了解基于线粒体核糖体蛋白功能的籽粒发育调控。
Mitochondrial respiration depends on proteins encoded by the nuclear and mitochondrial genomes. Many respiratory chain-related proteins are encoded by the mitochondrial genome and undergo translation by mitochondrial ribosomes. The newly identified maize (Zea mays) defective kernel44 (dek44) mutant produces small kernels showing embryo-lethal phenotypes. We cloned Dek44 by isolating the Mutator tag that produced the mutation and identified it as encoding a putative 50S ribosomal protein L9. Subcellular fractionation by ultracentrifugation confirmed that DEK44 is a mitochondrial ribosomal protein. DEK44 is highly conserved in monocots and only accumulates in kernels. Transcriptome and reverse transcription quantitative PCR analyses revealed that loss of DEK44 function affects the expression of genes encoding respiratory chain-related proteins from the mitochondrial and nuclear genomes. Blue native-PAGE revealed significantly reduced assembly of respiratory chain complexes in dek44 mutant kernels. Transmission electron microscopy indicated that the biogenesis and morphology of mitochondria were strongly affected in dek44 mutant kernels. Furthermore, DEK44 might regulate cell growth and kernel development via cyclin/cyclin-dependent kinase-mediated activities. This study provides insight into the regulation of kernel development based on mitochondrial ribosomal protein function.