MOLECULAR CHARACTERIZATION OF GNRH RECEPTORS

描述：（改编自申请人摘要）促性腺激素释放 促性腺激素释放激素（GnRH），通过其G蛋白偶联的高亲和力受体 位于垂体前叶的促性腺激素上，刺激分泌 促性腺激素（LH和FSH）。 目前已知GnRH受体（GnRHR） 也存在于垂体外组织、垂体反应性肿瘤和 肿瘤来源的细胞系，这表明GnRH可能起到额外的作用， 功能协调发展的 GnRHR的表达在表达上调和 通过其同源配体，通过性腺类固醇和肽下调。 然而，涉及改变表达率的机制， 分子水平的GnRHR尚不清楚。 为了理解规则 GnRHR基因在垂体、垂体外组织和 在激素反应性肿瘤中，PI分离了人GnRHR基因，并定义了 它的基因组结构。 人类GnRHR基因由两个内含子组成 和三个外显子，跨度超过20 kb。 它含有多个转录 起始位点和大量的推定的调控序列， 各种激素和其他调节因素增加了 受体基因的严格调节的差异表达， 组织特异性。 因此，GnRHR可能在调节 肿瘤的生长及其对各种刺激的反应性 和/或它的表达可能受到这些刺激的调节。 长期目标是在分子水平上理解DNA 这些成分和转录因子负责组织 人GnRHR基因的特异性表达和激素调节，以及 明确GnRH抑制肿瘤细胞生长的分子机制。 具体的目的是：1）表征以下的启动子序列： 垂体、垂体外组织和激素中GnRH受体基因 反应性肿瘤，2）为了研究GnRHR，转录调控由 雌激素、孕激素、糖皮质激素、睾酮、GnRH、阿糖胞苷、TPA和 cAMP，3）使用免疫组织化学方法鉴定肿瘤中表达GnRH受体的细胞。 单克隆抗体，以及4）测定GnRH和GnRHR在 正常组织和肿瘤组织。 这些研究可能会提供更大的 了解GnRH受体基因的调控，使我们能够 更好地了解其转录调节的复杂机制。 这些研究有可能为开发 一类用于治疗肿瘤反应性肿瘤的新药。

DESCRIPTION: (adapted from the applicants abstract) Gonadotropin releasing hormone (GnRH), through its G-protein -coupled, high-affinity receptor located on gonadotropes of the anterior pituitary, stimulates the secretion of gonadotropins (LH and FSH). It is now known that GnRH receptors (GnRHR) are also present in extra pituitary tissues, hormone-responsive tumors and tumors derived cell lines, suggesting that GnRH may serve additional functions. GnRHR expression is highly regulated in exhibiting both up and down regulation by its cognate ligand, by gonadal steroids and peptides. However, the mechanisms involved in altering the rate of expression of the GnRHR at molecular levels is unknown. In order to understand the regulation of GnRHR gene expression in the pituitary, extra-pituitary tissues and hormone responsive tumors, the PI isolated the human GnRHR gene and defined its genomic organization. The human GnRHR gene is composed of two introns and three exons, and spans over 20 kb. It contains multiple transcriptional initiation sites and a large number of putative regulatory sequences for various hormones and other regulatory factors raising the possibility of tightly-regulated, differential expression of the receptor gene, which may be tissue specific. Thus the GnRHR may play a key role in the regulation of hormone-responsive tumors growth and its responsiveness to various stimuli and/or it's expression may be regulated by such stimuli. The long termed goals are to understand at the molecular level the DNA components and transcriptional factors that are responsible for the tissue specific expression and hormonal regulation of the human GnRHR gene, and to define the molecular mechanism of inhibition of tumor cell growth by GnRH. The specific aims are: 1) To characterize the promoter sequence for GnRH-receptor gene in pituitary, extra-pituitary tissue and in hormone responsive tumors, 2) To study GnRHR, transcriptional regulation by estrogen, progesterone, glucocorticoid, testosterone, GnRH, inhibin, TPA and cAMP, 3) To identify the cells in tumors expressing GnRH receptor using a monoclonal antibody, and 4) To determine the expression of GnRH and GnRHR in normal and tumor tissues. These studies will likely provide a greater understanding of the regulation of the GnRH-receptor gene and allow us to better understand the complex mechanism of its transcriptional regulation. These studies have the potential to provide the basis for the development of a new class of drugs for treatments of hormone-responsive tumors.