Functional Analysis of Arabidopsis MADS-Box Genes

MADS盒基因编码的DNA结合调节蛋白在植物和动物的发育中发挥关键作用。在植物中，MADS盒基因调节花分生组织和花器官的身份， Yanofsky博士先前的研究已经导致了拟南芥MADS盒基因家族的许多成员的分离和初步表征。在目前的提案中，他计划将他的描述性研究扩展到功能水平，他将专注于参与雌蕊群和果实发育的三个基因的突变等位基因。AGL 8基因是正常心皮和果实发育所必需的，因为AGL 8突变体显示严重的果实异常。此外，AGL 8与APETALA 1和CAULIFLOWER基因一起在花的起始过程中起着冗余的作用。本研究拟通过一系列的分子和遗传实验来研究AGL 8与其他控制果实和心皮发育以及花分化早期的基因之间的相互作用。这些研究将为AGL 8的功能提供重要的见解，并将使Yanofsky博士能够将其作用整合到花启动和心皮和胚珠发育的新兴模型中。 Yanofsky博士在750个转基因品系的初始群体中通过同源重组确定了单一靶向破坏事件。虽然这清楚地表明了这一程序的可行性，但这类事件的发生频率尚待确定。这是特别重要的，因为如果频率大约是10-（，那么这已经代表了在其正常基因组环境中产生敲入和敲除突变的快速手段。然而，如果频率显著降低，则需要改进转化和/或选择策略。Yanofsky博士将把我们成功的努力扩展到使用同源重组作为工具。 Yanofsky博士将产生，构建和转基因植物，试图破坏另外三个MADS盒基因，包括AGL 4，AGL 15和AGL 20。

MADS-box genes encode DNA-binding regulatory proteins that play key roles in plant and animal development. In plants, MADS-box genes regulate flower-meristem and flower-organ identity, and Dr. Yanofsky's prior studies have led to the isolation and initial characterization of many members of the Arabidopsis MADS-box gene family. In the current proposal, he plans to extend his descriptive studies to the functional level where he will focus on mutant alleles of three of these genes involved in gynoecium and fruit development. The AGL8 gene is required for normal carpel and fruit development since agl8 mutants display severe fruit abnormalities. In addition, AGL8 plays a redundant role, together with the APETALA1 and CAULIFLOWER genes, during flower initiation. A series of molecular and genetic experiments are planned to investigate the interaction between AGL8 and other genes controlling fruit and carpel development as well as the early step of flower initiation. These studies should provide significant insights into the functions of AGL8 and will allow Dr. Yanofsky to integrate its role into emerging models for flower initiation and carpel- and ovule-development. Dr. Yanofsky has identified a single targeted disruption event by homologous recombination in an initial population of 750 transgenic lines. Although this clearly demonstrates the feasibility of this procedure, the frequency of such an event has yet to be determined. This is particularly important since, if the frequency is roughly 10-(, then this already represents a rapid means of creating knockin and knockout mutations in their normal genomic context. If, however, the frequency is significantly lower, then improvements in transformation and/or selection strategies will be needed. Dr. Yanofsky will extend our successful efforts to use homologous recombination as a tool. Dr. Yanofsky will generate, constructs, and transgenic plants in an attempt to disrupt three additional MADS-box genes, including AGL4, AGL15, and AGL20.