N-terminal domain-mediated homodimerization is required for photoreceptor activity of Arabidopsis CRYPTOCHROME 1
N-terminal domain-mediated homodimerization is required for photoreceptor activity of Arabidopsis CRYPTOCHROME 1
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DOI：
10.1105/tpc.104.029645
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发表时间：
2005-05-01
期刊：
影响因子：
11.6
通讯作者：
Yang, HQ
中科院分区：
文献类型：
--
作者：
Sang, Y;Li, QH;Yang, HQ
隐花色素（CRY）是蓝光受体，其与光解酶（催化UV光损伤的DNA的修复的黄素蛋白）共享序列相似性。将拟南芥CRY的C-末端结构域与GUS融合表达的转基因拟南芥幼苗表现出组成型光形态发生（COP）表型，表明拟南芥CRY的信号转导机制是通过C-末端结构域介导的。拟南芥CRY N-末端光裂合酶样结构域在CRY作用中的作用仍然知之甚少。在这里，我们报告的拟南芥EST 1 N-末端结构域（CNT 1）在光激活EST 1感光活性的重要作用。酵母双杂交试验、体外结合、体内化学交联、凝胶过滤和免疫共沉淀研究表明，p53 1以不依赖于光的方式同源二聚化。诱变和转基因研究表明，CNT 1介导的二聚化是光激活C-terminal domain of CT 11（CCT 1）所必需的。转基因数据和天然凝胶电泳研究表明，GUS的多聚化是负责和所需的介导的COP表型融合到CCT 1。这些结果表明GUS多聚体的性质类似于光修饰的CNT 1二聚体的性质。蓝光照射改变了CNT 1二聚体的性质，导致CCT 1发生变化，激活CCT 1，并最终触发CNT 1信号通路。
Cryptochromes (CRY) are blue light receptors that share sequence similarity with photolyases, flavoproteins that catalyze the repair of UV light-damaged DNA. Transgenic Arabidopsis thaliana seedlings expressing the C-terminal domains of the Arabidopsis CRY fused to beta-glucuronidase (GUS) display a constitutive photomorphogenic (COP) phenotype, indicating that the signaling mechanism of Arabidopsis CRY is mediated through the C-terminal domain. The role of the Arabidopsis CRY N-terminal photolyase-like domain in CRY action remains poorly understood. Here, we report the essential role of the Arabidopsis CRY1 N-terminal domain (CNT1) in the light activation of CRY1 photoreceptor activity. Yeast two-hybrid assay, in vitro binding, in vivo chemical cross-linking, gel filtration, and coimmunoprecipitation studies indicate that CRY1 homodimerizes in a light-independent manner. Mutagenesis and transgenic studies demonstrate that CNT1-mediated dimerization is required for light activation of the C-terminal domain of CRY1 (CCT1). Transgenic data and native gel electrophoresis studies suggest that multimerization of GUS is both responsible and required for mediating a COP phenotype on fusion to CCT1. These results indicate that the properties of the GUS multimer are analogous to those of the light-modified CNT1 dimer. Irradiation with blue light modifies the properties of the CNT1 dimer, resulting in a change in CCT1, activating CCT1, and eventually triggering the CRY1 signaling pathway.