The 5′-leader sequence of sugar beet mitochondrial atp6 encodes a novel polypeptide that is characteristic of Owen cytoplasmic male sterility
The 5′-leader sequence of sugar beet mitochondrial atp6 encodes a novel polypeptide that is characteristic of Owen cytoplasmic male sterility
复制标题
DOI：
10.1007/s00438-005-1140-y
复制
发表时间：
2005-04
影响因子：
3.1
通讯作者：
Masayuki P. Yamamoto;T. Kubo;T. Mikami
中科院分区：
文献类型：
--
作者：
Masayuki P. Yamamoto;T. Kubo;T. Mikami
细胞质雄性不育（CMS）是一种由染色体编码的性状，其特征是植物不能产生有活力的花粉。我们已经研究了正常（可育）或CMS细胞质的甜菜植物线粒体的蛋白质谱，并观察到欧文CMS植物中表达的35 kDa多肽，但在正常植物中不表达。在CMS线粒体中发现了35-kDa多肽的变体，这些线粒体位于五个不同的核背景中。有趣的是，这种多肽被证明是抗原相关的387-密码子ORF（preSatp 6），是融合在框内与下游atp 6。theatp 6 ORF的前序列延伸在高等植物中常见，但它是否正常表达迄今为止仍不清楚。因此，我们的研究是第一个证明atp 6前序列实际上是在线粒体中翻译的。我们还观察到preSATP 6是一种线粒体膜蛋白，可组装成均一的200-kDa蛋白复合物，在蛋白酶抑制剂存在下的细胞器翻译实验显示成熟preSATP 6的丰度随时间减少，表明成熟preSATP 6可能是由preSatp 6/Satp 6 ORF的翻译产物经蛋白水解加工而获得的。
Cytoplasmic male sterility (CMS) is a mitochondrially encoded trait, which is characterized by a failure of plants to produce viable pollen. We have investigated the protein profile of mitochondria from sugar beet plants with normal (fertile) or CMS cytoplasm, and observed that a 35-kDa polypeptide is expressed in Owen CMS plants but not in normal plants. The variant 35-kDa polypeptide was found in CMS mitochondria placed in five different nuclear backgrounds. Interestingly, this polypeptide proved to be antigenically related to a 387-codon ORF (preSatp6) that is fused in-frame with the downstreamatp6. The presequence extension of theatp6ORF is commonly found in higher plants, but whether or not it is normally expressed has hitherto remained unclear. Our study is thus the first to demonstrate that theatp6presequence is actually translated in mitochondria. We also observed that preSATP6 is a mitochondrial membrane protein that assembles into a homogeneous 200-kDa protein complex.In organellotranslation experiments in the presence of protease inhibitors showed a reduction in the abundance of mature preSATP6 with time, suggesting that the mature preSATP6 may be derived by proteolytic processing of a translation product of thepreSatp6/Satp6ORF.