AUREOCHROME, a photoreceptor required for photomorphogenesis in stramenopiles
AUREOCHROME, a photoreceptor required for photomorphogenesis in stramenopiles
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DOI：
10.1073/pnas.0707692104
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发表时间：
2007-12-04
影响因子：
11.1
通讯作者：
Kataoka, Hironao
中科院分区：
文献类型：
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作者：
Takahashi, Fumio;Yamagata, Daisuke;Kataoka, Hironao
在黄藻科的冷瓦氏藻和褐藻科的双列墨角藻中发现了蓝光受体。在沃氏藻中鉴定了两个同源物;每个同源物具有一个碱性区/亮氨酸拉链（bZIP）结构域和一个光氧电压（LOV）传感结构域。我们将这些色素蛋白命名为AUREOCHROME（AUREO 1和AUREO 2）。AUREO 1通过其LOV结构域结合黄素单甘肽，并形成390 nm吸收形式，表明BL照射后黄素单甘肽的C（4a）碳形成半胱氨酰加合物。加合物衰减到基态在约5分钟。其bZIP结构域结合的目标序列TGACGT。AUREO 1靶结合强烈增强BL治疗，这意味着AUREO 1作为BL调节的转录因子的功能。通过RNAi实验阐明了AUREO 1作为BL诱导分支的光感受器的功能。AUREO 2的RNAi出乎意料地诱导性器官原基而不是分支，暗示AUREO 2作为子开关启动分支的发育，而不是性器官的发育。AUREO序列也存在于海洋硅藻Thalassiosira damiana（硅藻纲）的基因组中，但不存在于绿色植物中。因此，金色素代表了光合层中的BL受体。
A blue light (BL) receptor was discovered in stramenopile algae Vaucheria frigida (Xanthophyceae) and Fucus distichus (Phaeophyceae). Two homologs were identified in Vaucheria; each has one basic region/leucine zipper (bZIP) domain and one light-oxygen-voltage (LOV)-sensing domain. We named these chromoproteins AUREOCHROMEs (AUREO1 and AUREO2). AUREO1 binds flavin mononucleotide via its LOV domain and forms a 390-nm-absorbing form, indicative of formation of a cysteinyl adduct to the C(4a) carbon of the flavin mononucleotide upon BL irradiation. The adduct decays to the ground state in approximate to 5 min. Its bZIP domain binds the target sequence TGACGT. The AUREO1 target binding was strongly enhanced by BL treatment, implying that AUREO1 functions as a BL-regulated transcription factor. The function of AUREO1 as photoreceptor for BL-induced branching is elucidated through RNAi experiments. RNAi of AUREO2 unexpectedly induces sex organ primordia instead of branches, implicating AUREO2 as a subswitch to initiate development of a branch, but not a sex organ. AUREO sequences are also found in the genome of the marine diatom Thalassiosira pseudonana (Bacillariophyceae), but are not present in green plants. AUREOCHROME therefore represents a BL receptor in photosynthetic stramenopiles.