Stimulus-reversible Co-repression in Regulation of a Plant bZIP Factor

[00927]乔纳森·阿里亚斯生物和工业活动导致环境中有机毒素的积累。通过改变碱性/亮氨酸-拉链（bZIP）转录因子的活性，增加核解毒基因的转录速率，从而提供细胞对这种“外源应激”剂的保护。动物和酵母的异种生物响应性bZIP因子的关键结构和调控特征已经被阐明。相比之下，人们对它们在植物中的功能对应物知之甚少。本研究的长期目标是了解涉及烟草bZIP因子TGA1a的转录如何受到细胞和应激线索的调节。最近有研究表明，2,4-二氯苯氧乙酸诱导的外源性应激可刺激TGA1a的dna结合和反式激活功能。一种名为p120的核tga1a结合蛋白，具有协同抑制因子的特性，与这些转录活性的应激反应性调节密切相关。PI的实验室将通过其克隆基因的体内功能研究来研究p120共同抑制因子的作用模式。TGA1a及其同源的as-1型顺式元件参与了许多植物解毒和宿主防御基因的调控。因此，阐明这一转录反应途径的分子基础，对于推进细胞解毒过程的基础知识，以及开发有效的遗传策略来操纵植物的天然保护基因具有重要意义。由于外源毒素在作物植物中积累并保持显著的潜在活性，旨在了解植物解毒途径的转录控制的研究可能对人类健康具有重要意义。

0091927 Jonathan AriasBiotic and industrial activities result in the environmental accumulation of organic toxins. Cellular protection against such "xenobiotic stress" agents is afforded by increasing the rate of transcription of nuclear detoxification genes, through changes in the activity of basic/leucine-zipper (bZIP) transcription factors. Key structural and regulatory features of xenobiotic-responsive bZIP factors of animals and yeast have been elucidated. By comparison, less is known about their functional counterparts in plants. The long-term goal of this research is to understand how transcription involving a tobacco bZIP factor termed TGA1a is regulated by cellular and stress cues. Recently it has been shown that xenobiotic stress induced by 2,4-dichlorophenoxyacetic acid can stimulate DNA-binding and trans-activation functions of TGA1a. A nuclear TGA1a-binding protein termed p120, with properties of a co-repressor, is strongly implicated in stress-responsive regulation of these transcription activities. The PI's laboratory will investigate the mode of action of the p120 co-repressor, through in vivo functional studies with its cloned gene. TGA1a and its cognate as-1-type cis-elements have been implicated in the regulation of a number of plant detoxification and host-defense genes. Thus, elucidating the molecular basis of this transcriptional response pathway is important for advancing basic knowledge of cellular detoxification processes, and for developing effective genetic strategies to manipulate natural protective genes of plants. Because xenobiotic toxins accumulate in crop plants and retain significant latent activity, research aimed at understanding plant transcriptional control of detoxification pathways may have important implications for human health.