A Flavin Binding Cryptochrome Photoreceptor Responds to Both Blue and Red Light in Chlamydomonas reinhardtii
A Flavin Binding Cryptochrome Photoreceptor Responds to Both Blue and Red Light in Chlamydomonas reinhardtii
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DOI：
10.1105/tpc.112.098947
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发表时间：
2012-07-01
期刊：
影响因子：
11.6
通讯作者：
Mittag, Maria
中科院分区：
文献类型：
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作者：
Beel, Benedikt;Prager, Katja;Mittag, Maria
隐色素是一种黄素蛋白，在昆虫、植物、真菌和细菌中起着感知蓝光受体的作用。本文研究了来自莱茵衣藻（Chlamydomonas reinhardtii）的一种隐色素，其序列与动物隐色素和（6-4）光解酶具有同源性。在蓝光和红光照射下，这种类似动物的隐色素（aCRY）会改变各种基因的光依赖性表达，这些基因编码的蛋白质与叶绿素和类胡萝卜素的生物合成、光收集复合物、氮代谢、细胞周期控制和生物钟有关。此外，暴露在黄光下而不是远红光下会导致特定基因的表达增加；这种表达在acry插入突变体中显著减少。这些体内效应与体外数据一致，表明aCRY中黄素的中性自由基状态可以吸收蓝光、黄光和红光，但远红光不被吸收。氧化黄素吸收蓝光后形成aCRY中性自由基。红色照明导致转换到完全还原状态。我们的数据表明，aCRY是一种功能重要的蓝光和红光激活的黄蛋白。广谱响应表明，中性自由基状态在aCRY中以暗形式发挥作用，并扩展了黄蛋白和隐色素作为蓝光传感器的范例，包括其他光质量。
Cryptochromes are flavoproteins that act as sensory blue light receptors in insects, plants, fungi, and bacteria. We have investigated a cryptochrome from the green alga Chlamydomonas reinhardtii with sequence homology to animal cryptochromes and (6-4) photolyases. In response to blue and red light exposure, this animal-like cryptochrome (aCRY) alters the light-dependent expression of various genes encoding proteins involved in chlorophyll and carotenoid biosynthesis, light-harvesting complexes, nitrogen metabolism, cell cycle control, and the circadian clock. Additionally, exposure to yellow but not far-red light leads to comparable increases in the expression of specific genes; this expression is significantly reduced in an acry insertional mutant. These in vivo effects are congruent with in vitro data showing that blue, yellow, and red light, but not far-red light, are absorbed by the neutral radical state of flavin in aCRY. The aCRY neutral radical is formed following blue light absorption of the oxidized flavin. Red illumination leads to conversion to the fully reduced state. Our data suggest that aCRY is a functionally important blue and red light-activated flavoprotein. The broad spectral response implies that the neutral radical state functions as a dark form in aCRY and expands the paradigm of flavoproteins and cryptochromes as blue light sensors to include other light qualities.