Metabolite regulation of cryptochrome 2 activity and flowering time

隐花色素2活性和开花时间的代谢调节

• 批准号: 262428688
• 负责人: Professor Dr. Alfred Batschauer
• 金额: --
• 依托单位: AG Molekulare Pflanzenphysiologie und Photobiologie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/262428688?language=en
• 关键词: Metabolite; regulation; cryptochrome; activity; flowering

The UV-A/blue light receptor cryptochrome 2 (cry2) has a central role in photoperiodic flower induction. Important components in cry2 signaling are bHLH transcription factors (CIB1, CIB2, CIB4, CIB5), which associate with cry2 under blue light. These heterodimers then bind to non-canonical E-boxes in the promoter region of FLOWERING LOCUS T (FT) and thereby induce expression of this important flowering gene. Moreover, cry2 interacts with SPA proteins and thereby inhibits the activity of the E3 ubiquitin ligase CONSTITUTIVE PHOTOMORPHOGENESIS 1 (COP1). COP1 plays a major role in degradation of the FT activator CONSTANS (CO). We have shown that the flavin chromophore of cry2 in the lit state is in the neutral semiquinone form, and formation of this redox state is enhanced by metabolites such as ATP and NADPH. Structure-based site-directed mutagenesis of CRY2 revealed which residues are required for metabolite control. This information will be used for elucidating the role of metabolites in photoperiodic flowering. For this purpose, we plan to express the cry2 variants in situ and to analyze their flowering time, FT expression, and interaction with downstream partners (CIB, SPA, COP1). These studies will be complemented by in vitro studies of recombinant proteins. In contrast to wild-type cry1, the cry1L407F mutant allele induces the expression of CO and FT and flowers early under short-day conditions. We showed that the tryptic digestion pattern of the cry1L407F protein in the dark is similar to that of wild-type cry1 in blue light, which suggests a light-independent lit-state structure of cry1L407F. We will determine whether cry1L407F uses the same signaling components as cry2 for the induction of FT. For this purpose, we will analyze flowering time and FT expression of the cry1L407F mutant in the cib1/cib2/cib5 mutant background as well as the interaction of cry1L407F with known partners of cry2. We intend to collaborate with the groups of Christian Jung (flowering control in Beta vulgaris) and Markus Schmid (regulation of flowering time by trehalose-6-phosphate signaling).

UV-A/蓝光受体隐色素2 （cry2）在光周期花诱导中起核心作用。cry2信号传导的重要组成部分是bHLH转录因子（CIB1, CIB2, CIB4, CIB5），它们在蓝光下与cry2相关。然后，这些异二聚体结合到开花位点T （FT）启动子区域的非规范e -box上，从而诱导这一重要开花基因的表达。此外，cry2与SPA蛋白相互作用，从而抑制E3泛素连接酶CONSTITUTIVE PHOTOMORPHOGENESIS 1 （COP1）的活性。COP1在FT激活剂CONSTANS （CO）的降解中起主要作用。我们已经证明，cry2在点燃状态下的黄素发色团是中性的半醌形式，并且这种氧化还原状态的形成被ATP和NADPH等代谢物增强。基于结构的CRY2位点定向突变揭示了代谢产物控制所需的残基。这些信息将用于阐明代谢产物在光周期开花中的作用。为此，我们计划原位表达cry2变异体，并分析其开花时间、FT表达以及与下游伙伴（CIB、SPA、COP1）的相互作用。这些研究将通过重组蛋白的体外研究加以补充。与野生型cry1相比，cry1L407F突变等位基因诱导CO和FT的表达，并在短日照条件下提前开花。我们发现cry1L407F蛋白在黑暗中的色氨酸消化模式与野生型cry1在蓝光下的相似，这表明cry1L407F具有不依赖于光的亮态结构。我们将确定cry1L407F是否使用与cry2相同的信号成分来诱导FT。为此，我们将分析在cib1/cib2/cib5突变背景下cry1L407F突变体的开花时间和FT表达，以及cry1L407F与cry2已知伴侣的相互作用。我们打算与Christian Jung （Beta vulgaris的开花控制）和Markus Schmid（海藻糖-6-磷酸信号调节开花时间）的团队合作。