REGULATION OF TSH GENES IN NOVEL THYROTROPE CELLS

促甲状腺激素（TSH）是垂体糖蛋白激素 负责合成和分泌甲状腺激素从 甲状腺因此，它在维护 甲状腺功能正常，是临床上必不可少的组成部分， 甲状腺癌和甲状腺癌等疾病的治疗方案 功能障碍实验室的长期目标是了解 促甲状腺细胞分化诱导的分子机制 脑垂体前叶利用靶向肿瘤发生， 在转基因小鼠中，我们建立了一种新的促甲状腺细胞系， 5.5 α T-1，表达促甲状腺细胞的分化标志物 脉该细胞系是一种独特的模型系统，其中分子 组织特异性基因调控的机制可以被剖析。的 本研究的主要目的是：1）鉴定顺式作用的DNA元件 α和β亚基促甲状腺细胞特异性表达所需 TSH基因这些研究将包括促甲状腺激素的鉴定- TSH亚单位5'侧翼区的特异性调节元件 使用瞬时转染测定法检测基因。后续DNA酶I保护 测定将确定促甲状腺激素结合的不同DNA结合元件 核因素。 2)检查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细胞将被 用TRH治疗，以表征他们对适当的 调节激素和信号转导级联。激素敏感 然后，将按照第一个具体目标分析这些要素。该分析 将提供必要的初步资料， 蛋白质因子和信号转导途径的表征 参与确定促甲状腺细胞的分化表型， 未来独立调查员补助金申请

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.