Nuclear genes required for post-translational steps in the biogenesis of the chloroplast cytochrome b6f complex in maize.
Nuclear genes required for post-translational steps in the biogenesis of the chloroplast cytochrome b6f complex in maize.
复制标题
玉米叶绿体细胞色素 b6f 复合物生物发生过程中翻译后步骤所需的核基因。
DOI：
10.1007/bf00290576
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Barkan,A
中科院分区：
文献类型：
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作者：
Voelker,R;Barkan,A
叶绿体cytochromeb6f复合体的生物发生所必需的核基因被确定的突变，导致特定的损失的复杂。我们描述了四个转座子诱导的玉米突变体，缺乏cytochromeb6f蛋白，但含有正常水平的其他光合复合物。这四个突变定义了两个核基因。为了确定每个突变阻断蛋白质积累的步骤，通过北方杂交分析检查编码每个亚基的mRNA，并在脉冲标记实验中检查亚基合成速率。在每个突变体中，编码复合物已知亚基的mRNA在大小和丰度上是正常的，并且主要亚基以正常速率合成。因此，这些突变在翻译后步骤阻断了细胞色素b6f复合物的生物合成。通过这些突变鉴定的两个核基因可能编码以前未知的亚基，参与辅基合成或连接，或促进复合物的组装。这些突变也被用来提供证据的真实性提出的复合物的第五个亚基，并证明在保护光系统11的光诱导降解的cytochromeb6f复合物的作用。
Nuclear genes essential for the biogenesis of the chloroplast cytochromeb6fcomplex were identified by mutations that cause the specific loss of the complex. We describe four transposon-induced maize mutants that lack cytochromeb6fproteins but contain normal levels of other photosynthetic complexes. The four mutations define two nuclear genes. To identify the step at which each mutation blocks protein accumulation, mRNAs encoding each subunit were examined by Northern hybridization analysis and the rates of subunit synthesis were examined in pulse-labeling experiments. In each mutant the mRNAs encoding the known subunits of the complex were normal in size and abundance and the major subunits were synthesized at normal rates. Thus, these mutations block the biogenesis of the cytochromeb6fcomplex at a post-translational step. The two nuclear genes identified by these mutations may encode previously unknown subunits, be involved in prosthetic group synthesis or attachment, or facilitate assembly of the complex. These mutations were also used to provide evidence for the authenticity of a proposed fifth subunit of the complex and to demonstrate a role for the cytochromeb6fcomplex in protecting photosystem 11 from light-induced degradation.