Regulation of APETALA2 in flower development in Arabidopsis

描述(申请人提供)：我们使用拟南芥中的花发育作为模型来理解多细胞生物体中的细胞如何承担它们的发育命运并形成不同的模式。我们的长期目标是识别和分析导致花原基细胞命运指定的遗传网络和潜在的分子相互作用。长期以来，花器官同源异型转录因子A、B和C基因一直是花器官特性规范中仅有的三类基因。我们的研究发现，一个名为miR172的microRNA是A类基因APETALA2的转录后抑制因子，表明转录后调控在花发育中也发挥作用。在拟议的项目中，我们将使用分子遗传学方法来确定miR172如何适合控制花发育的调控电路。特别是，我们希望1)通过分析突变体或RNAi系来确定5个MIR172基因的发育作用；2)确定miR172是否导致花原基中AP2表达的适当空间限制；3)研究ABC基因是否参与了miR172在花原基中高度特异的空间格局；以及4)测试miR172是否介导了A和C基因之间的拮抗相互作用。编码转录因子的同源异型基因在动物和植物中都起着决定细胞命运的作用。新出现的证据表明，在动物和植物中，microRNAs都是同源异型基因的调节者，这为控制细胞命运的已知转录网络增加了一层新的调节。这项拟议的研究无疑将为多细胞生物体的发育过程中转录后和转录机制的整合提供见解。

DESCRIPTION (provided by applicant): We use flower development in Arabidopsis as a model to understand how cells in multicellular organisms assume their developmental fates and form distinct patterns. Our long-term goal is to identify and analyze the genetic networks and the underlying molecular interactions that lead to cell fate specification in the floral primordium. For a long time, three classes of floral homeotic transcription factors known as the A, B, and C genes have been the only players in floral organ identity specification. Our studies have identified a microRNA, miR172, as a posttranscriptional represser of the class A gene APETALA2, indicating that posttranscriptional regulation also plays a role in flower development. In the proposed project, we will employ molecular genetic approaches to determine how miR172 fits in the regulatory circuitry governing flower development. In particular, we wish to 1) establish the developmental roles of the five MIR172 genes by analyzing mutants or RNAi lines; 2) determine whether miR172 leads to the proper spatial restriction of AP2 expression in the floral primordium; 3) investigate whether the ABC genes contribute to the highly specific spatial patterns of miR172 in the floral primordium; and 4) test whether miR172 mediates the antagonistic interactions between A and C genes. Homeotic genes that encode transcription factors act in cell fate specification in both animals and plants. Emerging evidence of microRNAs as regulators of homeotic genes in both animals and plants adds a new layer of regulation to the known transcriptional networks governing cell fate specification. This proposed research will undoubtedly provide insights into the integration of posttranscriptional and transcriptional mechanisms in developmental processes in multicellular organisms.