Frigerio Sara, Campoli Chiara, Zorzan Simone, Fantoni Luca Isaia, Crosatti Cristina, Drepper Friedel, Haehnel Wolfgang, Cattivelli Luigi, Morosinotto Tomas, Bassi Roberto
LGBP, UMR 6191 CEA-CNRS-Université de la Méditerranée, Marseille 13288, France.
J Biol Chem. 2007 Oct 5;282(40):29457-69. doi: 10.1074/jbc.M705132200. Epub 2007 Aug 5.
We analyze the effect of the plastoquinone redox state on the regulation of the light-harvesting antenna size at transcriptional and post-transcriptional levels. This was approached by studying transcription and accumulation of light-harvesting complexes in wild type versus the barley mutant viridis zb63, which is depleted in photosystem I and where plastoquinone is constitutively reduced. We show that the mRNA level of genes encoding antenna proteins is almost unaffected in the mutant; this stability of messenger level is not a peculiarity of antenna-encoding genes, but it extends to all photosynthesis-related genes. In contrast, analysis of protein accumulation by two-dimensional PAGE shows that the mutant undergoes strong reduction of its antenna size, with individual gene products having different levels of accumulation. We conclude that the plastoquinone redox state plays an important role in the long term regulation of chloroplast protein expression. However, its modulation is active at the post-transcriptional rather than transcriptional level.
我们在转录和转录后水平上分析了质体醌氧化还原状态对光捕获天线大小调节的影响。通过研究野生型与大麦突变体viridis zb63中光捕获复合体的转录和积累来实现这一点，该突变体中光系统I缺失，质体醌持续处于还原状态。我们发现，编码天线蛋白的基因的mRNA水平在突变体中几乎未受影响；信使水平的这种稳定性并非天线编码基因所特有，而是扩展到所有与光合作用相关的基因。相比之下，通过二维聚丙烯酰胺凝胶电泳对蛋白质积累的分析表明，该突变体的天线大小大幅减小，各个基因产物的积累水平不同。我们得出结论，质体醌氧化还原状态在叶绿体蛋白质表达的长期调节中起重要作用。然而，其调节作用在转录后而非转录水平上发挥作用。
