Differential regulation of psbA and psbD gene expression, and the role of the different D1 protein copies in the cyanobacterium Thermosynechococcus elongatus BP-1
Differential regulation of psbA and psbD gene expression, and the role of the different D1 protein copies in the cyanobacterium Thermosynechococcus elongatus BP-1
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DOI：
10.1016/j.bbabio.2007.10.015
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发表时间：
2008-01-01
影响因子：
4.3
通讯作者：
Vass, Imre
中科院分区：
文献类型：
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作者：
Kos, Peter B.;Deak, Zsuzsanna;Vass, Imre
在细长热聚球藻BP-1，这是在最近的PSII的结构研究的首选生物，三个psbA和两个psbD基因编码的三个D1和一个D2蛋白亚型，分别。这些基因和蛋白质产物的调节和功能在很大程度上是未知的。因此，我们使用定量RT-PCR来跟踪相应基因的mRNA水平的变化，结合生物物理测量来检测暴露于不同可见光和紫外光以及温度条件下光系统II的电子传递活性的变化。在适应40 ℃ 40 μ mol m（-2）s（-1）生长光照条件的细胞中，psb A和psbD转录物的主要群体分别来自psbA 1和psbD 1基因。当温度升高到60摄氏度时，psbA 1成为唯一的主要psbA mRNA种类。当细胞暴露于500 μ mol m（-2）S-1强度的可见光时，psbA 3取代psbA 1成为主要的psbA mRNA种类，psbD 2以psbD 1为代价增加。UV-B辐射还分别以psbA 1和psbD 1为代价增加了psbA 3和psbD 2的丰度。从不同程度的总D1蛋白损失的情况下，林可霉素的存在下，估计PsbA 3蛋白亚型取代PsbA 1在约65%的PSII中心后，2小时的高光驯化。在不同psbA转录本分布的条件下，利用叶绿素荧光和热释光测量方法，研究了S（2）Q（A）（-）和S（2）Q（B）（-）态的电荷复合特性。我们得到了更快的衰减的闪光诱导的叶绿素荧光在DCMU的存在下，以及较低的峰值温度的Q和B的热释光带时，PsbA 3取代PsbA 1作为主要的D1蛋白亚型。psbA和psbD转录水平的丰度以及D1蛋白异构体在T. elongatus的变化的环境条件进行了讨论。(C)2007 Elsevier B. V.保留所有权利。
In Thermosynechococcus elongatus BP-1, which is the preferred organism in recent structural studies of PSII, three psbA and two psbD genes code for three D1 and one D2 protein isoforms, respectively. The regulation and function of these genes and protein products is largely unknown. Therefore, we used quantitative RT-PCR to follow changes in the mRNA level of the respective genes, in combination with biophysical measurements to detect changes in the electron transport activity of Photosystem II under exposure to different visible and UV light, and temperature conditions. In cells which are acclimated to 40 mu mol m(-2) s(-1) growth light conditions at 40 degrees C the main populations of the psb A and psbD transcripts arise from the psbA1 and psbD1 genes, respectively. When the temperature is raised to 60 degrees C psbA1 becomes the single dominating psbA mRNA species. Upon exposure of the cells to 500 mu mol m(-2) S-1 intensity visible light psbA3 replaces psbA1 as the dominating psbA mRNA species, and psbD2 increases at the expense of psbD1. UV-B radiation also increases the abundance of psbA3, and psbD2 at the expense of psbA1 and psbD1, respectively. From the different extent of total D1 protein loss in the absence and presence of lincomycin it was estimated that the PsbA3 protein isoform replaces PsbA1 in about 65% of PSII centers after 2 h of high light acclimation. Under the conditions of different psbA transcript distributions chlorophyll fluorescence and thermoluminescence measurements were applied to monitor charge recombination characteristics of the S(2)Q(A)(-) and S(2)Q(B)(-) States. We obtained faster decay of flash-induced chlorophyll fluorescence in the presence of DCMU, as well as lower peak temperature of the Q and B thermoluminescence bands when PsbA3 replaced PsbA1 as the main D1 protein isoform. The relevance of dynamic changes in the abundance of psbA and psbD transcript levels, as well as D1 protein isoforms in the acclimation of T. elongatus to changing environmental conditions is discussed. (C) 2007 Elsevier B.V. All rights reserved.