CELL-SPECIFIC HORMONAL REGULATION OF GENE EXPRESSION

差异基因表达是细胞的潜在决定因素 复杂生物体中的多样性和分化细胞功能。因此， 需要阐明细胞特异性基因表达的基础 对发育和分化的分子理解。这个 特定基因的激活和/或抑制是由外部因素触发的 通过信号转导途径起作用的信息在很大程度上 无处不在。对于符合以下条件的基因，存在额外的复杂程度 受激素和生长因子的调节；这些基因可以表现出细胞- 诱导表达和基础表达的特异性。这个 我们研究的长期目标是了解荷尔蒙、 发育的和特定于组织的线索相结合，以精确控制 复杂基因的活性。这项提案的研究重点是 通过鉴定细胞特异性激素来研究细胞特异性激素的诱导 鸡卵清蛋白基因中的元件。该基因的这种表达是 仅限于禽类输卵管的管状腺细胞 受四类类固醇激素和多肽激素的调节 胰岛素。正在测试的特定假设是特定于细胞的 卵清蛋白基因的表达是通过以下方式实现的 输卵管激素与非输卵管未知因素的直接抑制 纸巾。具体目标是：1)。确定并描述 卵清蛋白基因中阳性的细胞特异性调控元件，II)。 克隆与阳性细胞特异性元件结合的蛋白质，并 三)。确定卵清蛋白基因中抑制其功能的元件 在不适当的组织中表达。身份识别和 相关DNA元素的表征将通过以下方式完成 体内足迹、凝胶迁移率变化分析和基因检测的结合 转化体。相关蛋白质的克隆将尝试通过 单杂交酵母遗传选择系统或通过其他技术 依赖于蛋白质的DNA结合特性。 阐明其产生和发展的潜在机制。 分化细胞的维持可能为 了解某些疾病(如癌症)中的事件是如何出错的 涉及细胞表型和增殖的广泛改变。 此外，禽类输卵管有可能产生大量的 大量易于纯化的蛋白质，如果表达可以靶向的话 管风琴。这对研究和治疗以及 出于商业目的。

Differential gene expression is the underlying determinant for cellular diversity and differentiated cell function in complex organisms. Thus, elucidation of the basis for cell-specific gene expression is required for a molecular understanding of development and differentiation. The activation and/or repression of specific genes is triggered by external messages that act through signal transduction pathways that are largely ubiquitous. An additional level of complexity exists for genes that are regulated by hormones and growth factors; those genes can exhibit cell- specificity for induced expression as well as for basal expression. The long term goal of our research is to understand how hormonal, developmental, and tissue-specific cues integrate to precisely control the activities of complex genes. The focus of the research in this proposal is to study cell-specific hormonal induction by identifying the cell-specific elements in the chicken ovalbumin gene. This expression of this gene is restricted to the tubular gland cells of the avian oviduct and is regulated by four classes of steroid hormones and by the peptide hormone insulin. The specific hypothesis being tested is that the cell-specific expression of the ovalbumin gene is achieved via positive activation by hormones in oviduct and direct repression by unknown factors in nonoviduct tissues. The Specific Aims are to I). identify and characterize the positive cell-specific regulatory elements in the ovalbumin gene, II). clone the proteins that bind to the positive cell-specific elements, and III). identify the elements in the ovalbumin gene that repress its expression in inappropriate tissues. The identification and characterization of the relevant DNA elements will be accomplished by combination of in vivo footprinting, gel mobility shift assays, and gene transfections. The cloning of the associated proteins will be attempted by a one-hybrid yeast genetic selection system or by other techniques that rely on the DNA binding properties of the proteins. Elucidation of the underlying mechanisms involved in the generation and maintenance of differentiated cells may provide the basis for understanding how events go awry in some diseases such as cancer that involve extensive alterations in cellular phenotype and proliferation. Furthermore, the avian oviduct has the potential for producing large amounts of easily purified proteins if expression can be targeted to that organ. This has implications for research and for therapeutic and commercial purposes.