ORFB is a subunit of F1FO-ATP synthase:: insight into the basis of cytoplasmic male sterility in sunflower
ORFB is a subunit of F1FO-ATP synthase:: insight into the basis of cytoplasmic male sterility in sunflower
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DOI：
10.1038/sj.embor.embor800
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发表时间：
2003-04-01
期刊：
影响因子：
7.7
通讯作者：
Leaver, CJ
中科院分区：
文献类型：
--
作者：
Sabar, M;Gagliardi, D;Leaver, CJ
ORR是在植物线粒体基因组中保守的基因的产物，并且基于序列基序和结构相似性，预测其是酵母和哺乳动物ATP 8的同源物，ATP 8是F1 FO-ATP合酶的F-O组分的一部分。我们已经表明，在向日葵中，orfB转录本被编辑，增加了预测蛋白与来自非植物物种的ATP 8蛋白的相似性。蓝色聚丙烯酰胺凝胶电泳和肽序列分析证实ORFB定位于ATP合酶复合物。预测的ORFB的氨基端19个氨基酸与嵌合线粒体ORF 522蛋白中的氨基酸相同，这与向日葵的细胞质雄性不育（CMS）有关。比较来自表达ORF 522的雄性不育系的呼吸复合物与来自雄性可育系的呼吸复合物的测定显示ATP合酶的ATP水解的特异性降低。这些观察使我们能够提出一个机制的CMS是与表达嵌合开放阅读框架包含部分orfB基因。
ORR is the product of a gene that is conserved in plant mitochondrial genomes, and which, on the basis of sequence motif and structural similarity, is predicted to be the homologue of yeast and mammalian ATP8, part of the F-O component of the F1FO-ATP synthase. We have shown that, in sunflower, orfB transcripts are edited increasing the similarity of the predicted protein to ATP8 proteins from non-plant species. Blue-native polyacrylamide gel electrophoresis and peptide sequencing confirm that ORFB localizes to the ATP synthase complex. The predicted amino-terminal 19 amino acids of ORFB are identical to those in the chimeric mitochondrial ORF522 protein, which is associated with cytoplasmic male sterility (CMS) in sunflower. Assays comparing respiratory complexes from a male-sterile line expressing ORF522 with those from a male-fertile line show a specific decrease in ATP hydrolysis by the ATP synthase. These observations allow us to propose a mechanism underlying CMS that is associated with the expression of chimeric open reading frames containing part of the orfB gene.