Light-dependent regulation of photosynthesis genes in Rhodobacter sphaeroides 2.4.1 is coordinately controlled by photosynthetic electron transport via the PrrBA two-component system and the photoreceptor AppA
Light-dependent regulation of photosynthesis genes in Rhodobacter sphaeroides 2.4.1 is coordinately controlled by photosynthetic electron transport via the PrrBA two-component system and the photoreceptor AppA
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DOI：
10.1111/j.1365-2958.2005.04882.x
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发表时间：
2005-11-01
影响因子：
3.6
通讯作者：
Klug, G
中科院分区：
文献类型：
--
作者：
Happ, HN;Braatsch, S;Klug, G
红细菌中光合装置的形成受氧张力和光强度的调节。在这里，我们表明，在厌氧生长的红细菌细胞中，编码光合复合物结构蛋白的 puc 和 puf 操纵子表达的光依赖性增加需要活跃的光合电子传输。光合作用基因的氧化还原敏感 CrtJ/PpsR 阻遏物被认为介导电子传递依赖性信号，但不参与该光依赖性信号链。我们的数据表明，光合反应中心引发的信号是通过球形红杆菌中的电子传递链组件和 PrrB/PrrA 双组分系统传递的。在缺氧的蓝光照射下，该信号会导致光合作用基因的激活，并干扰 R. sphaeroides 中由 AppA 光感受器和 PpsR 转录抑制子介导的蓝光抑制。因此，光感受器感知的光或启动光合作用电子传输的光对光合作用基因的转录具有相反的影响。两条信号通路都涉及氧化还原依赖性步骤，最终决定光对基因表达的影响。
Formation of the photosynthetic apparatus in Rhodobacter is regulated by oxygen tension and light intensity. Here we show that in anaerobically grown Rhodobacter cells a light-dependent increase in expression of the puc and puf operons encoding structural proteins of the photosynthetic complexes requires an active photosynthetic electron transport. The redox-sensitive CrtJ/PpsR repressor of photosynthesis genes, which was suggested to mediate electron transport-dependent signals, is not involved in this light-dependent signal chain. Our data reveal that the signal initiated in the photosynthetic reaction centre is transmitted via components of the electron transport chain and the PrrB/PrrA two-component system in Rhodobacter sphaeroides. Under blue light illumination in the absence of oxygen this signal leads to activation of photosynthesis genes and interferes with a blue-light repression mediated by the AppA photoreceptor and the PpsR transcriptional repressor in R. sphaeroides. Thus, light either sensed by a photoreceptor or initiating photosynthetic electron transport has opposite effects on the transcription of photosynthesis genes. Both signalling pathways involve redox-dependent steps that finally determine the effect of light on gene expression.