The cytoplasmic male-sterile type and normal type mitochondrial genomes of sugar beet share the same complement of genes of known function but differ in the content of expressed ORFs
The cytoplasmic male-sterile type and normal type mitochondrial genomes of sugar beet share the same complement of genes of known function but differ in the content of expressed ORFs
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DOI：
10.1007/s00438-004-1058-9
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发表时间：
2004-10-01
影响因子：
3.1
通讯作者：
Mikami, T
中科院分区：
文献类型：
--
作者：
Satoh, M;Kubo, T;Mikami, T
测定了甜菜细胞质雄性不育（CMS）线粒体基因组的全序列（501，020 bp）。这使我们能够将该序列与先前发表的正常雄性可育甜菜线粒体基因组序列进行比较。比较显示，这两个基因组具有相同的已知功能的基因互补。CMS线粒体基因组中编码的rRNA和tRNA基因与正常基因组中相应的对应物具有100%的序列同一性。我们在CMS线粒体基因组编码的11个蛋白质基因中发现了24个单核苷酸替换。然而，这些似乎都不是男性不育的原因。此外，还发现其他几个ORF在甜菜线粒体中被活跃地转录。其中，Norf 246被观察到存在于正常线粒体基因组中，但不存在于CMS基因组中。然而，Norf 246的丢失似乎不太可能与CMS的表达有因果关系，因为以前对线粒体翻译产物的研究未能检测到该ORF的产物。相反，CMS基因组包含四个转录的ORF（Satp 6前序列、Scox 2 -2、Sorf 324和Sorf 119），它们在正常基因组中缺失。这些ORF是CMS基因的潜在候选者，被证明是由线粒体基因组重排产生的。
The complete nucleotide sequence (501,020 bp) of the mitochondrial genome from cytoplasmic male-sterile (CMS) sugar beet was determined. This enabled us to compare the sequence with that previously published for the mitochondrial genome of normal, male-fertile sugar beet. The comparison revealed that the two genomes have the same complement of genes of known function. The rRNA and tRNA genes encoded in the CMS mitochondrial genome share 100% sequence identity with their respective counterparts in the normal genome. We found a total of 24 single nucleotide substitutions in 11 protein genes encoded by the CMS mitochondrial genome. However, none of these seems to be responsible for male sterility. In addition, several other ORFs were found to be actively transcribed in sugar beet mitochondria. Among these, Norf246 was observed to be present in the normal mitochondrial genome but absent from the CMS genome. However, it seems unlikely that the loss of Norf246 is causally related to the expression of CMS, because previous studies on mitochondrial translation products failed to detect the product of this ORF. Conversely, the CMS genome contains four transcribed ORFs (Satp6presequence, Scox2-2 , Sorf324 and Sorf119) which are missing from the normal genome. These ORFs, which are potential candidates for CMS genes, were shown to be generated by mitochondrial genome rearrangements.