Photoregulatory Signal Transduction

描述(申请人提供)：隐花色素蓝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处不在，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和藻类中。隐花色素介导的蓝光信号影响植物的多种过程，包括茎伸长、色素产生、基因表达、开花时间和昼夜节律的夹带。隐花色素也被描述用于动物，包括人类，它们在昼夜行为节律中发挥着重要作用。 表达隐花色素C-末端结构域的暗生长转基因拟南芥表现出与光生植物通常相关的特征，表明隐花色素的信号特性存在于该C-末端结构域内。显然，这种信号潜力在黑暗中被抑制在天然的隐色素分子中，这种抑制被光的作用所覆盖。在这里，我们建议定义在体外重建隐花色素依赖于光的信号活性所必需的因素。此外，我们还将确定在黑暗中抑制隐花色素信号活性所必需的隐花色素蛋白的机制和结构域。我们将使用微阵列来确定其表达依赖于隐染色质的基因，我们将进行染色质免疫沉淀研究，以表征隐染色素和其他信号伙伴与染色质的关联。最后，我们将进一步鉴定新的拟南芥突变体，这些突变体和隐花色素突变体一样，选择性地缺乏蓝光信号，因此定义了调控光信号过程的新基因。

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.