INITIAL EVENTS IN PHOTORECEPTOR SIGNALING

光感受器信号转导的初始事件

• 批准号: 2191423
• 负责人: JOANNE CHORY
• 金额: $ 22万
• 依托单位: SALK INSTITUTE FOR BIOLOGICAL STUDIES
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-05-01 至 1999-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2191423
• 关键词: Arabidopsis; SDS polyacrylamide gel electrophoresis; biological signal transduction; chimeric proteins; computer assisted sequence analysis; gene complementation; gene expression; gene mutation; immunoprecipitation; laboratory rabbit; light emission; molecular cloning; nonvisual photoreceptor; northern blottings; plant genetics; plant growth /development; plant proteins; polymerase chain reaction; protein sequence; restriction fragment length polymorphism; suppressor mutations

Light signals are required for the induction and regulation of many developmental processes in plants. The purpose of the proposal is to determine the primary event in photoreceptor signaling and to begin to unravel the control circuits of light-regulated development in plants. Though previous physiological and molecular studies have revealed the variety and complexity of plant responses to light, they have not answered questions about the mechanisms of those responses. Genetic analysis demonstrates that light responses are not simply endpoints of linear signal transduction pathways, but are the result of the integration of a variety of input signals through a complex network of interacting signaling components. As with other signal transduction systems, it is unclear whether relatively few signaling components regulate a multitude of responses, or whether the variety of responses correlates with a high number of specific regulatory molecules. Molecular biology and genetics have led to the identification of two main classes of regulatory components: Photoreceptor genes, encoding either red/far-red light receptors, phytochromes, or a putative blue-light receptor, and genes that act far downstream in the signal transduction pathway from the photoreceptor, presumably in the nucleus. It is proposed to use biochemical and genetic strategies to identify and characterize signal transduction components that act early in a phytochrome signal transduction pathway. The primary aims of these studies are (1) to identify proteins that interact directly with phytochrome B and to determine if these protein(s) interact solely with phytochrome B or also interact with other phytochromes; (2) to use genetics to identify components of signaling pathways that are specific to this particular phytochrome; (3) to clone at least one gene acting in a phytochrome B-specific pathway; and (4) to identify mutations in additional phytochromes. To identify proteins that interact directly with phytochrome B, we have used cloned PHYB sequences to identify genes from an Arabidopsis expression library that encode proteins that interact with the C-terminus of phytochrome B. The specificity of this interaction both in vivo and in vitro will be determined. To identify signaling components acting specifically downstream of the light-stable phytochrome B, but not downstream of the light-labile phytochrome A, we will identify and characterize genes whose activity is required for the expression of the phyB phenotype. In summary, the proposed experiments will further our knowledge of phytochrome-mediated signal transduction pathways, and will be a step toward elucidating how information is transmitted from photoreceptors in the cytoplasm to regulatory factors in the nucleus. The long-term objective is to completely understand the signal transduction network that allows plants to perceive and respond to their light environment, and to regulate this to general mechanisms of signal transduction in other organisms.

光信号是诱导和调节许多 植物的发育过程。该提案的目的是 确定光感受器信号传导中的主要事件，并开始 解开植物中光调节发育的控制回路。 尽管之前的生理和分子研究已经揭示了 植物对光的反应的多样性和复杂性，他们没有回答 这些反应的机制问题。遗传分析 表明光响应不是简单的线性终点， 信号转导途径，但结果的整合， 各种输入信号通过一个复杂的网络相互作用 信号组件。与其他信号转导系统一样， 不清楚相对较少的信号成分是否调节了大量的 或者是否反应的多样性与高 特定调节分子的数量。分子生物学和遗传学 导致了两个主要类别的监管识别 组件：光感受器基因，编码红光/远红光 受体，光敏色素，或推定的蓝光受体，和基因， 在信号转导通路的下游， 光感受器，大概在细胞核中。 提出使用 生物化学和遗传学策略来识别和表征信号 在光敏色素信号早期起作用的转导成分 转导途径。 这些研究的主要目的是（1）鉴定 直接与光敏色素B相互作用，并确定这些蛋白质 单独与光敏色素B相互作用或也与其它光敏色素相互作用 光敏色素;（2）使用遗传学来识别信号传导的成分 途径，这是特定的光敏色素;（3）克隆在 至少一个在光敏色素B特异性途径中起作用的基因;和（4） 鉴定其他光敏色素中的突变。来鉴定那些 直接与光敏色素B相互作用，我们已经使用克隆PHYB序列 从拟南芥表达文库中鉴定编码 与光敏色素B的C末端相互作用的蛋白质。的 这种相互作用在体内和体外的特异性将是 测定为了识别信号成分， 下游的光稳定光敏色素B，但不是下游的 光不稳定光敏色素A，我们将确定和表征基因， 活性是phyB表型表达所必需的。 总之，所提出的实验将进一步加深我们对以下问题的认识： 光敏色素介导的信号转导途径，并将是一个步骤 为了阐明信息是如何从光感受器中传递的， 将细胞质转化为细胞核中的调节因子。长期 目的是完全了解信号转导网络， 允许植物感知和响应它们的光环境， 调节这一信号转导的一般机制，在其他 有机体