Loss-of-function mutation in SCY1 triggers chloroplast-to-nucleus retrograde signaling in Arabidopsis thaliana
Loss-of-function mutation in SCY1 triggers chloroplast-to-nucleus retrograde signaling in Arabidopsis thaliana
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DOI：
10.1007/s10535-015-0514-1
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发表时间：
2015-07
影响因子：
1.5
通讯作者：
D. Liu;Z. Wu;L. Hou
中科院分区：
文献类型：
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作者：
D. Liu;Z. Wu;L. Hou
分泌途径是蛋白质跨类囊体膜进入类囊体腔的重要途径之一。本研究对两个编码SecY转座蛋白的拟南芥基因SCY 1和SCY 2进行了鉴定。半定量RT-PCR和GUS组织化学染色结果表明，SCY 1和SCY 2启动子在萌发种子、黄化子叶和花中有活性，但在根中无活性。特别是在绿色叶片中，SCY 1启动子控制的GUS基因几乎检测不到表达，而SCY 2启动子控制的GUS基因表达明显。此外，同源异源的scy 1 - 1植株可以异养生长，但对辐射敏感。进一步的研究表明，scy 1 - 1的叶绿体在早期发育阶段被阻滞，类囊体膜较少。实时荧光定量RT-PCR结果表明，在thesy 1 - 1突变体中，一些与叶绿素合成和光合作用有关的核基因表达量显著下降。这些结果表明SCY 1/2基因在拟南芥中受到发育和空间调控，SCY 1的功能缺失突变触发了叶绿体到核的逆向信号传导。
The secretory (Sec) pathway is one of the most important systems for transporting proteins across the thylakoid membrane into the lumen. TwoArabidopsisgenes encoding SecY translocon proteins, designatedSCY1andSCY2, were characterized in this study. Semi-quantitative RT-PCR and histochemical staining β-glucuronidase (GUS) activity reveal that bothSCY1andSCY2promoters were active in germinating seeds, etiolated cotyledons, and flowers, but not in roots. In particular, the expression ofGUSgene driven by theSCY1promoter was almost undetectable in green leaves, whereas GUS staining controlled by theSCY2promoter was clearly detected. Moreover, homozygousscy1-1plants could grow heterotrophically but appeared sensitive to radiation. Further studies show that chloroplasts ofscy1-1were arrested in early developmental stages with fewer thylakoid membranes. Real-time quantitative RT-PCR reveals that a number of nuclear-encoded genes involved in chlorophyll biosynthesis and photosynthesis were substantially down-regulated in thescy1-1mutant. All these results indicate that theSCY1/2genes were regulated developmentally and spatially, and a loss-of-function mutation inSCY1triggered chloroplast-to-nucleus retrograde signaling inArabidopsis thaliana.