Transcriptional Regulation in Early Flower Development

描述（申请人的描述）：本提案的长期目标 是了解器官特异性转录程序 发展模式已经启动。实验系统为花型 模式植物拟南芥中的模式，这是特别适合于 遗传和分子研究，因为它的世代时间短， 基因组和DNA介导的转化。具体问题是 研究LEAFY转录因子如何与其他因子相互作用 来调节花特异性基因的表达。通过比较 动物和植物的模式形成--进化出多细胞生物 这些过程背后的普遍原则可以是 发现了这些知识的健康相关性与出生缺陷有关 由环境影响引起的异常图案形成引起的，以及 遗传性疾病破坏了编码发育调节因子的基因。 LEAFY是已知最早的特异性转录因子， 在花原基中被激活，是转化为 营养枝变成花。与动物相比，LEAFY的独特之处在于 转录因子的一个重要作用是它可以被输出到相邻的细胞， 可以激活直接靶基因。一类直接靶基因，同源异型基因 控制花器官命运的，以前已经确定，包括 AGAMOUS基因然而，除了同源异型基因以外的其他靶点必须是 花的形成所需的，因为花是从芽不区分 不仅是器官特性的差异，还有器官排列的差异。 实验提出（1）研究AGAMOUS调节作为代理， 在植物发育过程中的转录控制;（2）揭示全球 表达式程序诱导LEAFY的目标是发现新的类， 靶基因;（3）确定LEAFY的顺式和反式要求 运动的目标是阐明这种独特的细胞-细胞模式， 通信拟议中的实验将促进我们对如何 广泛表达的早期作用基因参与调节 后作用基因，只在有限的区域表达的新兴 器官原基实验还将揭示不同的干细胞 沟通以实现花的协调发展。

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.