Molecular Control of Ovule Development

摘要拟南芥胚珠发育是研究基因表达的时间和模式在植物发育中的作用的一个有用的模式系统。 由于胚珠是种子的前体，种子是田间农业的主要产品，因此更好地了解胚珠发育具有有助于作物生产的潜力。INNER NO OUTER（INO）基因编码胚珠外珠被发育所必需的转录因子，外珠被是种皮外层的前体。INO特别适用于基因调控研究，因为它表现出严格调控的表达模式，相对较短的5 '侧翼DNA区域（INO启动子，P-INO）足以复制这种表达模式，并且已经开发了评估P-INO功能的稳健测定法。 在本研究中，负责INO调控的序列将被表征，直接上游效应子和下游靶标将被鉴定，P-INO内启动子活性所必需的特定序列基序将通过评估转基因植物中改变的元件的功能来确定。 含有鉴定的调控元件的片段将用于筛选相互作用的调控蛋白。 通过体外DNA结合试验、表达和突变体分析，将对选定的基因和基因产物进行分析，以评估胚珠发育和INO调控中的作用。通过使用DNA微阵列技术评估大多数拟南芥基因在各种拟南芥胚珠突变体中的表达水平，将对胚珠发育过程中的基因表达进行分析。 表达数据将用于鉴定新的胚珠调控基因和组装控制胚珠发育的分子相互作用模型，该研究的完成将有助于我们对高等植物生殖发育调控的认识和对形态发生的分子控制的全面理解。 这项研究可以通过利用已确定的监管相互作用，并通过本科生和研究生的跨学科教育，促进种子作物的改善，从而产生更广泛的影响。

AbstractArabidopsis ovule development is a useful model system to study the roles of timing and patterning of gene expression in plant development. Because ovules are the precursors to seeds, the major products of field agriculture, better understanding of ovule development has the potential to contribute to crop productivity.The INNER NO OUTER (INO) gene encodes a transcription factor essential for development of the ovule outer integument, the precursor to the outer layer of the seed coat. INO is especially suitable for gene regulation studies because it exhibits a tightly regulated pattern of expression, a relatively short region of 5'-flanking DNA (the INO promoter, P-INO) is sufficient to reproduce this expression pattern, and robust assays to evaluate P-INO function have been developed. In the current study, sequences responsible for INO regulation will be characterized and immediate upstream effectors and downstream targets will be identified.Specific sequence motifs within P-INO necessary for promoter activity will be defined through evaluating the function of altered elements in transgenic plants. Fragments containing identified regulatory elements will be used to screen for interacting regulatory proteins. In vitro DNA-binding assays, expression and mutant analysis will be performed on selected genes and gene products to evaluate roles in ovule development and INO regulation.Analysis of gene expression during ovule development will be performed by evaluating the level of expression of most Arabidopsis genes in various Arabidopsis ovule mutants using DNA microarray technology. The expression data will be used to identify new ovule regulatory genes and to assemble a model of molecular interactions governing ovule development.Completion of the proposed research will contribute to our knowledge of regulation of reproductive development in higher plants and to a general understanding of molecular control of morphogenesis. This research can have broader impacts by facilitating improvements in seed crops through exploitation of identified regulatory interactions, and through interdisciplinary education of undergraduate and graduate students.