ANALYSIS OF A LIGHT-REGULATED DEVELOPMENT SWITCH

光控显影开关的分析

• 批准号: 6351193
• 负责人: XING WANG DENG
• 金额: $ 48.1万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-08-01 至 2004-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6351193
• 关键词: Arabidopsis; biological signal transduction; gene expression; gene mutation; genetic regulatory element; indoleacetate; intermolecular interaction; molecular cloning; nonvisual photoreceptor; photobiology; plant genetics; plant growth /development; site directed mutagenesis; transcription factor

How environmental signals are perceived by living organisms and integrated to modulate their key developmental regulators to control gene expression and development program is a fundamental question of biology. The long-term goal of this research is to dissect the molecular and cellular basis of how light signals are integrated to achieve the control of the development mode switch, employing the light-regulated seedling development of Arabidopsis thaliana as an experimental system. A multidisciplinary approach in our past effort have established working model that in darkness, COP1 (constitutively photomorphogenic 1) acts inside the nucleus to suppress the photomorphogenic development, via directly interacting with and negatively regulating specific transcription factors whose activities are responsible for promoting photomorphogenesis. While light abolishes COP1 nuclear accumulation and abrogates its repressive action. Here I propose to extend our current investigation through a combination of molecular genetic, cell biological, and biochemical approaches. To confirm our working model and reveal the molecular insights of COP1 action, we will further examine the regulatory role of the best defined COP1 and HY5 interaction in vivo, and to illuminate how this interaction translates into the regulation of HY5 stability, and its ability to interact with its target promoters and regulate their expression. To illustrate the molecular basis and mechanism of COP1's ability to interact with multiple targets and regulate pleiotropic development processes, we shall further analyze the role of four new putative downstream targets which specifically interact with the WD-40 repeats domain of COP1 and reveal how they specifically contact the distinct interactive surfaces defined by those seven WD-40-repeats. As a first step to understand how light regulate COP1 activity, we will further characterize a recently cloned signaling component which play a key role in phyA inactivation of COP1 and whose expression is also regulated by hormone auxin. To achieve a more comprehensive picture of this regulatory switch, we will pursue molecular cloning and characterization of two additional key regulatory components that defined by two separate genetic screens. If time permits, in vitro reconstitution system will be developed using our defined components and further genetic screens will be carried to reveal additional regulatory components. Those studies will provide novel insights into the mechanism of how an environmental signal achieves its control of an organism's development program. Since all the COP proteins defined so far are highly conserved among all multicellular eukaryotic organisms including human, the fundamental mechanism gained in this Arabidopsis model system will provide a guidance for understanding the function of those conserved regulators in human and thus enhance our ability to combat human health problems.

活生物体如何看待环境信号，并整合以调节其关键的发育调节剂来控制基因表达和发展计划是一个基本的生物学问题。 这项研究的长期目标是剖析光信号如何整合以实现开发模式开关的控制的分子和细胞基础，并采用了拟南芥作为实验系统的光调节的幼苗开发。 在过去的努力中，一种多学科的方法建立了工作模型，即在黑暗中，COP1（组成性光生形态学1）在核内作用，通过直接与促进光生形态发生的活性直接相互作用并负面调节特定的转录因子，从而抑制光性发育。 尽管光消除了COP1核积累并消除了其抑制作用。在这里，我建议通过分子遗传，细胞生物学和生化方法的结合来扩展当前的研究。 为了确认我们的工作模型并揭示COP1作用的分子见解，我们将进一步研究体内最佳定义的COP1和HY5相互作用的调节作用，并阐明这种相互作用如何转化为HY5稳定性的调节，以及其与目标启动子相互作用并调节其表达的能力。 为了说明COP1与多个靶标相互作用并调节多效性开发过程的能力的分子基础和机制，我们将进一步分析四个新推定的下游目标的作用，这些靶标特异性地与COP1的WD-40重复域进行了专门相互作用，并揭示了它们如何特异性地与这些七个WD-40-40-40- repeats-repeats-repeats界定的独特的交互式。 作为了解光如何调节COP1活性的第一步，我们将进一步表征最近克隆的信号成分，该信号成分在COP1的Phya失活中起关键作用，并且其表达也受激素生长素的调节。 为了实现这种调节转换的更全面的了解，我们将追求两个由两个单独的遗传筛选定义的其他关键调节组件的分子克隆和表征。 如果时间允许，将使用我们确定的组件开发体外重构系统，并将携带进一步的遗传筛选以揭示其他调节组件。这些研究将提供有关环境信号如何控制生物体开发计划的机制的新见解。 由于到目前为止定义的所有COP蛋白在包括人类在内的所有多细胞真核生物中都是高度保守的，因此在这种拟南芥模型系统中获得的基本机制将为理解人类中那些保守的调节剂的功能提供指导，从而增强了我们对解决人类健康问题的能力。