MOLECULAR CONTROL OF FLOWER DEVELOPMENT IN ARABIDOPSIS

我实验室的研究重点是了解 控制十字花科植物拟南芥的花发育。 在 在拟南芥中，同源异型调控基因Apetala 2（Ap 2）的突变可以 导致萼片向心皮和花瓣的同源异型转化， 雄蕊，以及花器官发育的其他戏剧性变化。 很明显，Apetala 2基因在决定 花器官原基的发育和植物生殖的调控。 然而，对于该基因在分子水平上的功能， 水平 最近，我和同事从拟南芥中克隆了Ap 2基因， 通过插入诱变。 Ap 2核苷酸序列的分析 没有提供任何有意义的线索，这个基因的功能在细胞中。 因此，本提案中的实验旨在产生新的 Apetala 2结构的分子和遗传学见解， 拟南芥发育过程中该基因的空间调控， 与花的遗传控制中涉及的其他基因位点的相互作用 发展 首先，确定结构和/或功能上重要的 我们将比较野生型Ap 2基因的核苷酸序列 Ap 2及其侧翼DNA序列与几种化学诱导突变体 等位基因 此外，我们将确定是否有几个有趣的图案 在Ap 2氨基酸序列中的氨基酸序列对该基因的功能至关重要， 使用体外定点突变产生一组新的突变等位基因， 诱变结合这些突变基因的转化 回到拟南芥中。 我们研究的第二个目标是了解 Ap 2与其他参与调控的拟南芥基因位点相互作用 花器官发生的过程 定义相互作用和/或上位性 Ap 2和其他已知的调控基因位点之间的关系，我们建议 观察Ap 22基因表达的时间和空间调控， 利用原位杂交和免疫定位的突变体植物 程序. 最后，为了鉴定与Ap 2相互作用的新基因， 确定花器官原基的身份，我们建议筛选 诱变的ap 2植物用于同源异型表型修饰--显性 AP 2的增强子和抑制子突变体。 这种基因筛查应该 确定控制花卉的调控网络的其他要素 包括调节子、辅因子以及下游靶点的开发 ap 2基因 总之，这些研究应该提供新的见解， 控制植物格局形成和繁殖的分子过程。

Research in my laboratory is focused on understanding the processes controlling flower development in the crucifer Arabidopsis thaliana. In Arabidopsis, mutations in the homeotic regulatory gene Apetala2 (Ap2) can cause the homeotic transformation of sepals to carpels and petals to stamens, as well as other dramatic changes in floral organ development. Clearly, the Apetala2 gene plays a central role in determining the identity of floral organ primordia and the regulation of plant reproduction. However, nothing is known about the function of this gene at the molecular level. Recently, my colleagues and I cloned the Ap2 gene from Arabidopsis by insertional mutagenesis. Analysis of the Ap2 nucleotide sequence has not provided any meaningful clues to this gene's function in the cell. Therefore, the experiments in this proposal are designed to generate new molecular and genetic insights into the structure of Apetala2, the temporal and spatial regulation of this gene during Arabidopsis development, and its interactions with other gene loci involved in the genetic control of flower development. First, to identify structurally and/or functionally important regions of the Ap2 gene we will compare the nucleotide sequence of wildtype Ap2 and its flanking DNA sequences with several chemically induced mutant alleles. In addition, we will determine whether several interesting motifs in the Ap2 amino acid sequence are critical for this gene's function by generating a set of new mutant alleles using in vitro site-directed mutagenesis in conjunction with the transformation of these mutant genes back into Arabidopsis. A second goal of our research is to understand how Ap2 interacts with other Arabidopsis gene loci involved in the regulation of floral organogenesis. To define the interactions and/or epistatic relationships between Ap2 and other known regulatory gene loci, we propose to look at the temporal and spatial regulation of Ap22 gene expression in mutant plants using in situ hybridization and immunolocalization procedures. Finally, to identify new genes that interact with Ap2 to determine the identity of floral organ primordia, we propose to screen mutagenized ap2 plants for modifiers of the homeotic phenotype -- dominant enhancer and suppressor mutants of ap2. This genetic screen should identify additional elements of the regulatory network controlling flower development including regulators, cofactors, as well as downstream target genes of ap2. Together, these studies should provide new insight into the molecular processes controlling plant pattern formation and reproduction.