Transcriptional Regulation in Early Flower Development

描述(申请人的描述)：本提案的长期目标 是为了理解转录程序是如何在器官特异性的基础上 启动了发展模式。该实验系统是花卉的 模式植物拟南芥中的图案，这特别适合于 遗传和分子研究因其世代时间短、体积小 基因组，以及简易的DNA介导性转化。具体的问题是 研究了LEAFY转录因子如何与其他因子相互作用 来调控花特异基因的表达。通过比较以下过程： 动物和植物的模式形成--进化出多细胞 独立--这些过程背后的普遍原则可以是 没有遮盖物。这些知识的健康相关性与出生缺陷有关。 由环境影响导致的异常图案形成所致，以及 基因紊乱会破坏编码发育调节剂的基因。 LEAFY，这是已知的最早的特异性转录因子 在花原基中被激活，是转换的必要条件和充分条件 营养枝开成花。与动物相比，树叶的独特之处 转录因子是它可以输出到相邻的细胞，在那里它 可以激活直接靶基因。S的一类直接靶点，同源异型基因 控制花器官命运的基因，以前已经被发现，包括 AGAMOUS基因。然而，除了同源异型基因之外，其他靶点必须是 是花形成所必需的，因为花不同于嫩枝 不仅因为器官身份的不同，而且还因为器官排列的不同。 建议进行以下实验：(1)研究AGAMOUS规则作为 植物发育过程中的转录调控；(2)揭示全球 由LEAFY诱导的表达程序，目标是发现新的类别 目的基因；以及(3)鉴定LEAFY基因的顺式和反式要求 运动，目的是阐明细胞-细胞的这一独特模式 沟通。拟议中的实验将增进我们对 广泛表达的早期作用基因参与调节 仅在新生生物的限制性区域表达的后期作用基因 器官原基。这些实验还将揭示不同的干细胞如何 沟通，实现花卉的协调发展。

DESCRIPTION (Applicant's Description): The long-term objective of this proposal is to understand how transcriptional programs underlying organ-specific patterns of development are initiated. The experimental system is floral patterning in the model plant Arabidopsis, which is particularly suited for genetic and molecular studies because of its short generation time, small genome, and facile DNA-mediated transformation. The specific problem to be investigated is how the LEAFY transcription factor interacts with other factors to regulate flower-specific gene expression. By comparing the processes of pattern formation in animals and plants -- which evolved multicellularity independently -- universal principles underlying these processes can be uncovered. The health relevance of such knowledge relates to birth defects resulting from aberrant pattern formation caused by environmental effects, and to genetic disorders disrupting genes encoding developmental regulators. LEAFY, which is the earliest known transcription factor to be specifically activated in floral primordia, is both necessary and sufficient for converting vegetative shoots into flowers. A unique feature of LEAFY compared to animal transcription factors is that it can be exported to adjacent cells, where it can activate direct target genes. One class of direct target s, homeotic genes that control floral organ fate, has been previously identified, and includes the AGAMOUS gene. However, other targets besides homeotic genes must be required for flower formation, since flowers are distinguished from shoots not only by differences in organ identity but also in organ arrangement. Experiments are proposed (1) to study AGAMOUS regulation as a proxy for transcriptional control during plant development; (2) to reveal the global expression program induced by LEAFY with the goal of uncovering new classes of target genes; and (3) to identify the cis- and trans-requirements for LEAFY movement with the goal of elucidating this unique mode of cell-cell communication. The proposed experiments will advance our understanding of how widely expressed, early acting genes participate in the regulation of later-acting genes that are expressed only in restricted regions of an emerging organ primordium. The experiments will also reveal how different stem cells communicate to effect coordinated development of the flower.