Analysis of Apetala3 and Pistillata Floral Homeotic Gene Function

Apetala3和Pistillata花同源异型基因功能分析

• 批准号: 9904876
• 负责人: Vivian Irish
• 金额: $ 37.5万
• 依托单位: Yale University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-10-01 至 2002-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9904876&HistoricalAwards=false
• 关键词: Analysis; Apetala3; Pistillata; Floral; Homeotic

In Arabidopsis, two floral homeotic genes, APETALA3 (AP3) and PISTILLATA (PI), are required for the formation of petals and stamens. AP3 and PI are both expressed in petal and stamen primordia, consistent with their proposed organ identity roles. AP3 and PI both encode MADS-box proteins; the MADS-box is required for DNA binding and has been found in a number of other yeast and mammalian transcription factors. AP3 and PI bind to DNA as an obligate heterodimer, and several lines of evidence suggest that the specificity of AP3/PI action may depend on interactions with other cofactors as well as on protein modification. This proposal aims to investigate how the action of the AP3 and PI proteins is regulated. A modified one-hybrid screen is proposed to identify cofactors that interact with AP3 and PI to modulate their biological specificity. Since both AP3 and PI contain a conserved potential phosphorylation site, it is possible that protein modification may also play a role in modulating AP3/PI action. Immunoprecipitation experiments and transgenic studies will be used to ascertain whether the phosphorylation status of AP3 and/or PI plays a role in modifying their function. Finally, AP3 and PI may act in a non-cell autonomous fashion, indicating that these gene products may play a role in intercellular signaling. Plants mosaic for AP3 (or PI) will be generated using a modified Ac/Ds system. Mosaic patches generated at different times in floral ontogeny will define the temporal parameters of AP3 (or PI) action. In addition, anti-AP3 and anti-PI antibodies will be used to assess whether AP3 and PI proteins actually traffic between cells to effect their non-autonomous functions. Using complementary biochemical, genetic, and developmental approaches to elucidate the mechanisms by which AP3 and PI act will provide a framework for uderstanding how these floral homeotic gene products attain functional specificity. Furthermore, these analyses should be valuable in beginning to define the mechanisms by which plant cells communicate with each other to coordinate their growth and differentiation.

在拟南芥中，花瓣和雄蕊的形成需要两个花同源基因 APETALA3 (AP3) 和 PISTILLATA (PI)。 AP3 和 PI 均在花瓣和雄蕊原基中表达，这与它们提出的器官身份作用一致。 AP3 和 PI 均编码 MADS-box 蛋白； MADS-box 是 DNA 结合所必需的，并且已在许多其他酵母和哺乳动物转录因子中发现。 AP3 和 PI 作为专性异二聚体与 DNA 结合，多项证据表明 AP3/PI 作用的特异性可能取决于与其他辅因子的相互作用以及蛋白质修饰。 该提案旨在研究 AP3 和 PI 蛋白的作用如何受到调节。 提出了一种改进的单杂交筛选来识别与 AP3 和 PI 相互作用以调节其生物特异性的辅因子。 由于 AP3 和 PI 都含有保守的潜在磷酸化位点，因此蛋白质修饰也可能在调节 AP3/PI 作用中发挥作用。 免疫沉淀实验和转基因研究将用于确定 AP3 和/或 PI 的磷酸化状态是否在改变其功能中发挥作用。 最后，AP3 和 PI 可能以非细胞自主方式发挥作用，表明这些基因产物可能在细胞间信号传导中发挥作用。 AP3（或 PI）的植物镶嵌将使用改进的 Ac/Ds 系统生成。 花个体发育中不同时间产生的花叶斑块将定义 AP3（或 PI）作用的时间参数。 此外，抗 AP3 和抗 PI 抗体将用于评估 AP3 和 PI 蛋白是否确实在细胞之间运输以影响其非自主功能。 使用互补的生化、遗传和发育方法来阐明 AP3 和 PI 的作用机制将为理解这些花同源异型基因产物如何实现功能特异性提供一个框架。 此外，这些分析对于开始定义植物细胞相互通信以协调其生长和分化的机制应该是有价值的。