Regulation of APETALA2 in flower development in Arabidopsis

描述（由申请人提供）：我们以拟南芥的花发育为模型来理解多细胞生物中的细胞如何承担它们的发育命运并形成不同的模式。我们的长期目标是鉴定和分析导致花原基细胞命运规范的遗传网络和潜在的分子相互作用。长期以来，花同源性转录因子a、B和C基因一直是花器官身份规范的唯一参与者。我们的研究已经发现了一个microRNA miR172作为a类基因APETALA2的转录后抑制因子，这表明转录后调控在花的发育中也起作用。在拟议的项目中，我们将采用分子遗传学方法来确定miR172如何适应控制花发育的调节电路。特别是，我们希望1)通过分析突变体或RNAi系来确定五个MIR172基因的发育作用；2)确定miR172是否导致AP2在花原基中的表达受到适当的空间限制；3)探究ABC基因是否对miR172在花原基中高度特异性的空间格局有贡献；4)检测miR172是否介导A和C基因间的拮抗相互作用。编码转录因子的同源基因在动物和植物细胞命运规范中起作用。在动物和植物中，microrna作为同源基因的调节因子的新证据为已知的控制细胞命运规范的转录网络增加了一个新的调节层。这项拟议的研究无疑将为多细胞生物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.