Composite Auxin Response Elements and the Auxin Signal Transduction Pathway

复合生长素反应元件和生长素信号转导途径

• 批准号: 9603678
• 负责人: Thomas Guilfoyle
• 金额: $ 33万
• 依托单位: University of Missouri-Columbia
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-04-01 至 2001-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9603678&HistoricalAwards=false
• 关键词: Composite; Auxin; Response; Elements; Signal

9604208 Guilfoyle The plant hormone auxin is involved in or controls a wide variety of developmental processes. Auxin-induced cell division, cell elongation and cell differentiation all involve distinct patterns of gene expression. A variety of early or primary response genes that are specifically induced by auxin have been identified in these growth and developmental processes. Most of the early auxin response genes are expressed in a tissue-specific and organ-specific manner in the absence of exogenous auxin application. To observe a substantial induction of these genes by exogenous auxin, it generally is necessary first to deplete auxin by bathing excised organs in auxin-free medium. Soybean GH3 is an early auxin response gene that differs from others in four important ways. First, it is expressed at very low levels in the absence of exogenous auxin application. Second, GH3 mRNA can be induced at least 50-fold in seedlings and plants without subjecting excised organs to the auxin depletion protocol. Third, the gene is induced in virtually every cell, tissue or organ of a seedling or plant. Fourth, the GH3 promoter is highly responsive to auxin in a variety of heterologous plant species whether assayed transiently in protoplasts or in stable transformants. The GH3 gene promoter consists of at least three separate auxin response elements (AuxRE) within 250 base pairs of the transcription start site, which have been characterized with respect to independent function, tissue/organ-specific expression, DNA sequence, and auxin responsiveness. Moreover, novel AuxREs have been constructed that are equivalent or several fold more inducible by auxin than natural AuxREs or the entire GH3 promoter, and transcription factors have been cloned that bind specifically to composite AuxREs. This research will use both natural composite and more active synthetic AuxREs to precisely determine how AuxREs function in auxin-responsive promoters, and to identify transcription factors that interact with composite AuxREs and determine their mechanism of action. The plant hormone auxin is involved in or controls a wide variety of developmental processes. Auxin-induced cell division, cell elongation and cell differentiation all involve distinct patterns of gene expression. A variety of early or primary response genes that are specifically induced by auxin have been identified in these growth and developmental processes. Soybean GH3 is an early auxin response gene that is induced in virtually every cell, tissue or organ of a seedling or plant. The regulatory region (promoter) of the GH3 gene consists of at least three separate auxin response elements (AuxRE) which have been characterized with respect to independent function, tissue/organ-specific expression, DNA sequence, and auxin responsiveness. Moreover, novel AuxREs have been constructed that are equivalent or several fold more active than natural AuxREs. This research will use both natural composite and more active synthetic AuxREs to precisely determine how AuxREs function, and to identify transcription factors that interact with AuxREs and determine their mechanism of action.

9604208 Guilfoyle植物激素生长素参与或控制多种发育过程。 生长素诱导的细胞分裂、细胞伸长和细胞分化都涉及不同的基因表达模式。 在这些生长和发育过程中，已经鉴定出多种由生长素特异性诱导的早期或初级反应基因。 大多数早期生长素反应基因在不施加外源生长素的情况下以组织特异性和器官特异性的方式表达。 为了观察外源生长素对这些基因的大量诱导，通常需要首先通过将切除的器官浸泡在无生长素的培养基中来耗尽生长素。 大豆GH 3基因是一个早期生长素反应基因，它与其他基因有四个重要的区别。 首先，在没有外源生长素应用的情况下，它以非常低的水平表达。 第二，GH 3 mRNA可以在幼苗和植物中诱导至少50倍，而不使切除的器官经受生长素耗竭方案。 第三，该基因在幼苗或植物的几乎每个细胞、组织或器官中被诱导。 第四，GH 3启动子在多种异源植物物种中对生长素高度响应，无论是在原生质体中还是在稳定转化体中瞬时测定。 GH 3基因启动子在转录起始位点的250个碱基对内由至少三个独立的生长素应答元件（auxin response elements，AUCRE）组成，其特征在于独立功能、组织/器官特异性表达、DNA序列和生长素应答。 此外，已经构建了与天然GH 3启动子或整个GH 3启动子相比，生长素可诱导的新GH 3RE等同或数倍，并且已经克隆了特异性结合复合GH 3RE的转录因子。 这项研究将使用天然的复合材料和更活跃的合成材料来精确地确定复合材料在生长素响应启动子中的功能，并确定与复合材料相互作用的转录因子并确定其作用机制。 植物激素生长素参与或控制多种发育过程。 生长素诱导的细胞分裂、细胞伸长和细胞分化都涉及不同的基因表达模式。 在这些生长和发育过程中，已经鉴定出多种由生长素特异性诱导的早期或初级反应基因。 大豆GH 3是一种早期生长素反应基因，其在幼苗或植物的几乎每个细胞、组织或器官中被诱导。GH 3基因的调控区（启动子）由至少三个独立的生长素反应元件（AuxinResponseElements，AuxinRE）组成，其特征在于独立功能、组织/器官特异性表达、DNA序列和生长素反应性。 此外，已经构建了活性等同于或数倍于天然β-内酰胺酶的新型β-内酰胺酶。 这项研究将使用天然复合物和更活跃的合成的BERREs来精确地确定BERREs如何发挥作用，并确定与BERREs相互作用的转录因子并确定其作用机制。