cpSecA, a thylakoid protein translocase subunit, is essential for photosynthetic development in Arabidopsis
cpSecA, a thylakoid protein translocase subunit, is essential for photosynthetic development in Arabidopsis
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cpSecA 是一种类囊体蛋白易位酶亚基，对于拟南芥的光合作用发育至关重要
DOI：
10.1093/jxb/erq033
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发表时间：
2010-04-01
影响因子：
6.9
通讯作者：
Wang, Ning Ning
中科院分区：
文献类型：
--
作者：
Liu, Dong;Gong, Qingqiu;Wang, Ning Ning
内共生体衍生的sec依赖性蛋白质分选途径是蛋白质进入类囊体管腔的必要条件，对叶绿体的正常功能也很重要。对拟南芥叶绿体Sec易位机制的atp酶亚基cpSecA的两个功能缺失突变体进行了分析。纯合突变体在自养条件下呈白化和幼苗致死，在外源碳供应下保持矮化和不育。在正常光照条件下，它们受到氧化应激和积累超氧化物的影响。电镜观察显示，突变体叶绿体类囊体结构发育不全。AtcpSecA::GUS转基因植株的组织化学GUS实验证实，AtcpSecA在绿色器官中以光诱导方式表达。实时RT-PCR和微阵列分析显示，突变体中光合复合物的细胞核和叶绿体编码亚基的转录受到抑制，叶绿体蛋白易位机制和线粒体编码的呼吸复合物的转录受到诱导。由此推断，AtcpSecA在叶绿体的生物发生中起着至关重要的作用，缺乏AtcpSecA会触发逆行信号，最终导致叶绿体和线粒体基因表达的重编程。
The endosymbiont-derived Sec-dependent protein sorting pathway is essential for protein import into the thylakoid lumen and is important for the proper functioning of the chloroplast. Two loss-of-function mutants of cpSecA, the ATPase subunit of the chloroplast Sec translocation machinery, were analysed in Arabidopsis. The homozygous mutants were albino and seedling lethal under autotrophic conditions and remained dwarf and infertile with an exogenous carbon supply. They were subject to oxidative stress and accumulated superoxide under normal lighting conditions. Electron microscopy revealed that the chloroplast of the mutants had underdeveloped thylakoid structures. Histochemical GUS assay of the AtcpSecA::GUS transgenic plants confirmed that AtcpSecA was expressed in green organs in a light-inducible way. Real-time RT-PCR and microarray analysis revealed repressed transcription of nucleus- and chloroplast- encoded subunits of photosynthetic complexes, and induced transcription of chloroplast protein translocation machinery and mitochondrion-encoded respiratory complexes in the mutants. It is inferred that AtcpSecA plays an essential role in chloroplast biogenesis, the absence of which triggered a retrograde signal, eventually leading to a reprogramming of chloroplast and mitochondrial gene expression.