Photoregulatory Signal Transduction

描述（由申请人提供）：隐色素蓝光光感受器首先在植物拟南芥中被描述。这些光感受器即使不是无所不在，也广泛存在于整个植物界，显然存在于所有高等植物以及蕨类植物和藻类中。隐花色素介导的蓝光信号影响多种植物过程，包括茎伸长、色素产生、基因表达、开花时间和昼夜节律的影响。隐色素也被描述为动物，包括人类，它们在昼夜行为节律中起着至关重要的作用。

DESCRIPTION (provided by applicant): The cryptochrome blue light photoreceptors were first described in the plant Arabidopsis. These photoreceptors are widespread, if not ubiquitous, throughout the plant kingdom, apparently present in all higher plants as well as ferns and algae. Cryptochrome-mediated blue light signaling affects a variety of plant processes including stem elongation, pigment production, gene expression, flowering time, and the entrainment of circadian rhythms. Cryptochromes have also been described for animals, including humans, where they play an essential role in circadian behavioral rhythms. Dark-grown transgenic Arabidopsis plants expressing the C-terminal domain of cryptochrome exhibit features that are normally associated with light-grown plants, indicating that the signaling properties of cryptochrome reside within this C-terminal domain. Apparently this signaling potential is repressed in the native cryptochrome molecule in the dark, this repression being overridden by the action of light. Here we propose to define the factors that are necessary to reconstruct in vitro the light-dependent signaling activity of cryptochrome. In addition, we will define the mechanism and the domain of the cryptochrome protein necessary for repressing cryptochrome signaling activity in the dark. We will use microarrays to identify genes whose expression is dependent on cryptochrome and we will perform chromatin immunoprecipitation studies to characterize the association of cryptochrome and other signaling partners with chromatin. Finally, we will further characterize new mutants of Arabidopsis that, like cryptochrome mutants, are selectively deficient in blue light signaling and therefore define new genes that regulate the light signaling process.