Transcript processing internal to a mitochondrial open reading frame is correlated with fertility restoration in male-sterile sorghum.
Transcript processing internal to a mitochondrial open reading frame is correlated with fertility restoration in male-sterile sorghum.
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DOI：
10.1046/j.1365-313x.1996.10010123.x
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发表时间：
1996-07
期刊：
影响因子：
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通讯作者：
H. V. Tang;D. Pring;L. Shaw;R. A. Salazar;F. R. Muza;B. Yan;K. Schertz
中科院分区：
文献类型：
--
作者：
H. V. Tang;D. Pring;L. Shaw;R. A. Salazar;F. R. Muza;B. Yan;K. Schertz
高粱细胞质雄性不育系IS 1112 C的嵌合线粒体DNA（mtDNA）构型包括命名为orf 107的321 bp开放阅读框，编码11.85 kDa的预测多肽产物。开放阅读框架，类似于其他几个与cms相关的基因，由来自专性基因的氨基末端序列组成。然而，与迄今为止的其他例子不同，羧基末端序列与水稻cms orf 79中涉及的开放阅读框架的羧基末端高度相似。orf 107的氨基端31个残基与atp9的相似性为84%，羧基端49个残基与orf 79的羧基端的相似性为57%和80%。orf107的转录本被编辑，有四个C到U的变化，改变了氨基酸。部分或完全恢复生育力的高粱系表现出高效率的内部orf107转录加工活动，排除丰富的全长转录，而雄性不育系表现出只有一个痕迹的活动。先前关于雄性不育系与雄性可育系中细胞器合成多肽中12kDa的丰度的数据与这些系的差异orf 107转录物加工活性相关。回交和F2系的检查表明恢复的配子体模式，并表明增强的转录加工活性是必要的，但不足以恢复完全的生育能力。这些新的观察结果表明，不同物种中与cms相关的线粒体开放阅读框架可以包括高度相似的基序，并且育性恢复可能涉及一种机制，通过该机制，cms相关基因产物的合成可能通过内部转录物切割而被排除。
A chimeric mitochondrial DNA (mtDNA) configuration of the cytoplasmic male-sterile (cms) sorghum line IS1112C includes a 321 bp open reading frame designated orf107, encoding a predicted polypeptide product of 11.85 kDa. The open reading frame, similar to several other genes associated with cms, consists of amino-terminal sequences derived from an obligate gene. Unlike other examples to date, however, the carboxy-terminal sequences are highly similar to the carboxy terminus of an open reading frame implicated in cms of rice, orf79. The amino-terminal 31 residues of orf107 are 84% similar to atp9, and the carboxy-terminal 49 residues are 57% identical and 80% similar to the carboxy terminus of orf79. Transcripts of orf107 are edited, with four C-to-U changes that alter amino acids. Sorghum lines partially or fully restored to fertility exhibit a high-efficiency internal-orf107 transcript processing activity, precluding abundant whole-length transcripts, while male-sterile lines exhibit only a trace of the activity. Previous data on the abundance of a 12kDa in organello-synthesized polypeptide in male-sterile versus male-fertile lines are correlated with differential orf107 transcript processing activity of these lines. Examinations of backcross and F2 lines suggest a gametophytic mode of restoration, and indicate that enhanced transcript processing activity is necessary, but not sufficient, to restore full fertility. These novel observations indicate that mitochondrial open reading frames associated with cms in different species can include highly similar motifs, and that fertility restoration could involve a mechanism by which synthesis of a cms-associated gene product may be precluded through internal transcript cleavage.