Plant Photosensory Receptor CRY2 Signaling Mechanism

描述(申请人提供)：太阳辐射是地球上所有真核生物的最终能源，它还提供关于时间、季节和周围环境的信息。生物体如何对光作出反应，以及光感受器如何调节光反应，代表了生物学中的一些基本问题。隐花色素是一种蓝/UV-A光感受器，也是已知的唯一在植物和动物中都起作用的光感受器。隐花色素的功能不仅限于控制植物的光形态发生发育；它们在生物钟和光周期中的功能也被发现影响复杂的人类健康问题，如癌症、睡眠障碍和其他行为障碍。研究隐色素如何调控植物发育将增加我们对生命的一个基本方面的了解，这些研究产生的知识也与改善人类健康有关。我们最近发现蓝光诱导的隐花色素磷酸化在隐花色素的功能和调控中起着关键作用，并鉴定了大约100个CRY2作用的主要靶基因。我们还开发了新的遗传学屏幕来识别影响隐花色素功能的突变，包括SEC(Cry1Cr2的抑制子)、ECC(Cr1Cr2的增强子)和Coc(CRY2-GFP过表达抵消因子)。我们已经克隆了9个SCC基因和1个ECC基因。本研究的目的是：(1)研究隐花色素磷酸化的生化机制；(2)研究CRY2在蓝光下如何影响其可能的主要靶基因的表达；(3)继续鉴定和克隆SCC、ECC和COC基因，并研究我们已经鉴定的SCC基因，特别是SCC4-D(可能的E3环)和SCC5-D(可能的激酶)，如何在拟南芥中介导隐花色素信号转导。

DESCRIPTION (provided by applicant): Solar radiation is the ultimate energy source for all eukaryotes on earth, and it also provides information about the time, season, and surrounding environments. How organisms respond to light and how photosensory receptors mediate light responses represent some of the fundamental questions in biology. Cryptochrome is a blue/UV-A light receptor and the only photoreceptor known to function in both plants and animals. The function of cryptochromes is not limited to the control of plant photomorphogenetic development; their functions in the circadian clock and photoperiodism have also been found to affect complex human health problems such as cancer, sleep disorders, and other behavioral disorders. Investigation of how cryptochromes regulate plant development would increase our understanding of a fundamental aspect of life, and the knowledge resulting from such studies is also relevant to the improvement of human health. We have recently discovered that blue light-induced cryptochrome phosphorylation play key roles in the function and regulation of cryptochromes and identified approximate 100 primary target genes of CRY2 action. We have also developed the new genetics screens to identify mutations affecting cryptochrome functions, including sec (suppressors of cry1cry2), ecc (enhancers of cry1cry2), and coc (CRY2-GFP overexpression counteractor). We have cloned 9 SCC genes, and one ECC gene. The objectives of this proposal are (1) to investigate the biochemical mechanism of cryptochrome phosphorylation; (2) to study how CRY2 affects expressions of its putative primary target genes in response to blue light, and (3) to continue identify and clone the SCC, ECC, and COC genes, and to investigate how the SCC genes that we have identified, especially SCC4-D (a putative RING E3) and SCC5-D (a putative kinase), may mediate cryptochrome signal transduction in Arabidopsis.