Targeted destabilization of HY5 during light-regulated development of Arabidopsis
Targeted destabilization of HY5 during light-regulated development of Arabidopsis
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DOI：
10.1038/35013076
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发表时间：
2000-05-25
期刊：
影响因子：
64.8
通讯作者：
Deng, XW
中科院分区：
文献类型：
--
作者：
Osterlund, MT;Hardtke, CS;Deng, XW
拟南芥幼苗显示出不同的发育模式，这取决于环境光。在光照下生长的幼苗发育为光形态发生，其特征为短的下胚轴和展开的绿色子叶。相反，在黑暗中生长的幼苗会黄化，下胚轴伸长，子叶在顶端钩上闭合。光信号被多个光感受器感知并转导到下游调节器，以定量的方式决定光形态发生发育的程度。两个关键的下游组分COP 1和HY 5在调节幼苗发育中起拮抗作用（1）。HY 5是一种bZIP转录因子，可直接与光诱导基因的启动子结合，促进其表达和光形态发生发育（2，3）。COP 1是一种具有WD-40重复序列的环指蛋白，其核丰度受光负调控（4，5）。COP 1直接与细胞核中的HY 5相互作用，以负向调节其活性（1）。在这里，我们表明，HY 5的丰度与光形态发生发展的程度直接相关，并且COP 1-HY 5相互作用可能特异性地靶向HY 5在细胞核中进行蛋白酶体介导的降解。
Arabidopsis seedlings display contrasting developmental patterns depending on the ambient light. Seedlings grown in the light develop photomorphogenically, characterized by short hypocotyls and expanded green cotyledons. In contrast, seedlings grown in darkness become etiolated, with elongated hypocotyls and closed cotyledons on an apical hook. Light signals, perceived by multiple photoreceptors and transduced to downstream regulators, dictate the extent of photomorphogenic development in a quantitative manner. Two key downstream components, COP1 and HY5, act antagonistically in regulating seedling development(1). HY5 is a bZIP transcription factor that binds directly to the promoters of light-inducible genes, promoting their expression and photomorphogenic development(2,3). COP1 is a RING-finger protein with WD-40 repeats whose nuclear abundance is negatively regulated by light(4,5). COP1 interacts directly with HY5 in the nucleus to regulate its activity negatively(1). Here we show that the abundance of HY5 is directly correlated with the extent of photomorphogenic development, and that the COP1-HY5 interaction may specifically target HY5 for proteasome-mediated degradation in the nucleus.