A blue-light-activated adenylyl cyclase mediates photoavoidance in Euglena gracilis
A blue-light-activated adenylyl cyclase mediates photoavoidance in Euglena gracilis
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DOI：
10.1038/4151047a
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发表时间：
2002-02-28
期刊：
影响因子：
64.8
通讯作者：
Watanabe, M
中科院分区：
文献类型：
--
作者：
Iseki, M;Matsunaga, S;Watanabe, M
蓝光调节植物和真菌的发育以及微生物的行为等过程(1，2)。已鉴定出两种蓝光受体黄素蛋白：与光解酶(3，4)有部分相似性的隐色素(3，4)和光调节蛋白激酶(5，6)。前者也在动物身上发现，有证据表明它们在昼夜节律中起着重要作用(7，8)。单细胞鞭毛虫Euglena gracilis在入射蓝光强度突然增加或减少后，突然改变游泳方向，即增强或降低恐光反应，分别导致光回避或光积累(9)。虽然眼镜蛇的这些光行为已经研究了一个世纪(10)，但调节它们的光感受器分子仍然未知(9)。本文报道了一种新型蓝光受体黄素蛋白--光活化的腺酰环化酶在纤细眼虫光感受器细胞器中的发现和生化特性，分子遗传学证据表明它介导了增强的畏光反应。
Blue light regulates processes such as the development of plants and fungi and the behaviour of microbes(1,2). Two types of blue-light receptor flavoprotein have been identified: cryptochromes, which have partial similarity to photolyases(3,4), and phototropins, which are photoregulated protein kinases(5,6). The former have also been found in animals with evidence of essential roles in circadian rhythms(7,8). Euglena gracilis, a unicellular flagellate, abruptly changes its swimming direction after a sudden increase or decrease in incident blue light intensity, that is, step-up or step-down photophobic responses, resulting in photoavoidance or photoaccumulation, respectively(9). Although these photobehaviours of Euglena have been studied for a century(10), the photoreceptor molecules mediating them have remained unknown(9). Here we report the discovery and biochemical characterization of a new type of blue-light receptor flavoprotein, photoactivated adenylyl cyclase, in the photoreceptor organelle of Euglena gracilis, with molecular genetic evidence that it mediates the step-up photophobic response.