REGULATION OF TSH GENES IN NOVEL THYROTROPE CELLS

促甲状腺激素(TSH)是一种垂体糖蛋白激素 负责甲状腺激素的合成和分泌 甲状腺。因此，它在维护 甲状腺功能正常，是临床必备的组成部分 甲状腺癌和甲状腺等疾病的治疗方案 失灵了。该实验室的长期目标是了解 促甲状腺激素分化的分子机制 在脑下垂体前叶。使用靶向肿瘤发生在 转基因小鼠，我们创造了一种新的促甲状腺细胞系，名为 5.5αT-1，表达促甲状腺激素的分化标志物 血统。这个细胞系是一个独特的模型系统，在这个系统中，分子 可以对组织特异性基因调控的机制进行剖析。这个 这个项目的目标是：1)识别顺式作用的DNA元件 促甲状腺激素α和β亚基的特异性表达所必需的 促甲状腺激素基因。这些研究将包括鉴定促甲状腺激素- 促甲状腺激素亚单位5‘侧翼区的特异性调控元件 基因的瞬时转染法。后续DNase I保护 化验将定义不同的与促甲状腺激素结合的DNA结合元件 核因素。2)检测TSH亚单位基因的激素调节 促甲状腺激素释放激素(TRH)。5.5AlphaT-1电池将是 用TRH治疗来表征他们对适当的 调节荷尔蒙和信号转导级联反应。激素反应 然后将按照第一个具体目标对要素进行分析。这一分析 将提供必要的初步信息，以便进一步 蛋白质因子与信号转导途径的研究进展 参与确定促甲状腺细胞的分化表型 未来的独立调查员拨款申请。

Thyroid stimulating hormone (TSH) is the pituitary glycoprotein hormone responsible for the synthesis and secretion of thyroid hormone from the thyroid gland. As such, it plays a crucial role in the maintenance of normal thyroid function, and is a necessary component in clinical treatment regimes for diseases such as thyroid cancer and thyroid disfunction. The long term goals of the laboratory are to understand the molecular mechanisms dictating the induction of thyrotrope differentiation in the anterior pituitary gland. Using targeted tumorigenesis in transgenic mice, we have created a novel thyrotrope cell line, termed 5.5alphaT-1, which expresses differentiated markers of the thyrotrope lineage. This cell line is a unique model system in which the molecular mechanism of tissue-specific gene regulation can be dissected. The objectives of this project are to: 1) Identify the cis-acting DNA elements required for thyrotrope-specific expression of the alpha- and beta-subunit genes of TSH. These studies will include the identification of thyrotrope- specific regulatory elements in the 5' flanking regions of the TSH subunit genes using transient transfection assays. Subsequent DNAse I protection assays will define distinct DNA-binding elements bound by thyrotrope nuclear factors. 2) Examine the hormonal regulation of TSH subunit genes by Thyrotropin Releasing Hormone (TRH). The 5.5alphaT-1 cells will be treated with TRH to characterize their response to the appropriate regulatory hormone and signal transduction cascades. Hormone-responsive elements will then be analyzed as in the first specific aim. This analysis will provide the necessary preliminary information for further characterization of the protein factors and signal transduction pathways involved in specifying the differentiated phenotype of thyrotrope cells in a future Independent Investigator grant application.