RNA METABOLISM IN DEVELOPMENT AND HORMONAL REGULATION

目的是了解激素如何调节基因表达， 将病毒引起的基因表达变化与 生长和发育中的细胞介导的变化。 具体研究 目的是分析生长素调控的基因表达在植物生长中的作用， 大豆幼苗组织中由这种激素介导的生长反应。 的 主要感兴趣的生长反应是细胞伸长的控制， 生长素和生长素诱导大量组织增殖。 一些 的cDNA克隆已被分离，并将进一步克隆。 鉴定，其是代表其细胞质 浓度增加或减少迅速和选择性后，生长素 治疗 这些mRNA的表达将在不同的时间段进行评估。 发育阶段，生长素诱导的生长，以及生长素与 其他激素和生长调节剂，导致改变和/或 异常的生长反应 编码这些生长素反应mRNAs的基因 将进行测序，以a）确定氨基酸序列和一些 所编码蛋白质的性质，B）鉴定 可能对它们的表达的调节很重要，以及c）定义 用于肽合成和抗体的蛋白质的抗原区 生产 抗体将用于确定细胞定位 的相关蛋白质，并量化其丰度在所指出的 增长转型。 生长素反应基因将被克隆到T-DNA中 载体并用于转化实验。 这些实验 旨在评估哪些序列对发育和 基因表达的调控模式。 此外，他们将 评估基因过度表达的生理后果（使用 非常强的组成型或诱导型启动子）或表达不足 该基因（使用这些相同的启动子来表达负链， 抑制mRNA的翻译）。 随着我们对 生长素调控基因表达在植物生理反应中作用 生长素（例如细胞伸长或细胞增殖），并在定义 在控制这些基因表达中重要的顺式元件， 反式作用因子的分析， 这些基因将被启动。

The objectives are to understand how hormones regulate gene expression and to correlate hormone-induced changes in gene expression with hormone-mediated changes in growth and development. The specific research aims are to analyze the role(s) of auxin-regulated gene expression in the growth responses mediated by this hormone in soybean seedling tissues. The growth responses of major interest are the control of cell elongation by auxin and the induction of massive tissue proliferation by auxin. A number of cDNA clones have been isolated, and additional clones will be identified, which are representative of mRNAs whose cytoplasmic concentrations increase or decrease rapidly and selectively following auxin treatment. The expression of these mRNAs will be assessed during various developmental stages, auxin-induced growth, and interactions of auxin with other hormones and growth regulators which result in altered and/or aberrant growth responses. Genes that encode these auxin-responsive mRNAs will be sequenced in order a) to determine the amino acid sequence and some properties of the encoded protein, b) to identify conserved regions which may be important to the regulation of their expression, and c) to define antigenic regions of the protein for peptide synthesis and antibody production. Antibodies will be used to identify the cellular localization of the relevant proteins and to quantify their abundance during the noted growth transitions. Auxin responsive genes will be cloned into T-DNA vectors and used in transformation experiments. These experiments are designed to evaluate which sequences are important to the developmental and hormone-regulated pattern of gene expression. Additionally, they will assess the physiological consequences of over expression of the gene (using very strong constitutive or inducible promoters) or of under expression of the gene (using these same promoters to express the negative strand to suppress translation of the mRNA). As progress is made in understanding the role of auxin-regulated gene expression during physiological responses to auxin (e.g. cell elongation or cell proliferation) and in defining cis-elements important in controlling the expression of these genes, analyses of trans-acting factors essential in the selective regulation of these genes will be initiated.