Molecular Mechanisms of Hormone Regulated Gene Expression in the Pituitary

垂体激素调节基因表达的分子机制

• 批准号: 7371164
• 负责人: JOHN H. NILSON
• 金额: $ 37.09万
• 依托单位: WASHINGTON STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-15 至 2013-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7371164
• 关键词: 3' Untranslated Regions; Address; Affect; Alleles; Binding; Biological; Cell Line; Colon Carcinoma; Complex; Consensus; Cues; Cyclic AMP-Dependent Protein Kinases; DNA-Binding Proteins; Data; Dependency; Disease; Docking; Elements; Endocrine System Diseases; Ensure; Exhibits; Family; Fertility; Follicle Stimulating Hormone; Future; G-Protein-Coupled Receptors; Gametogenesis; Gene Expression; Gene Expression Profile; Gene Family; Gene Transfer Techniques; Generic Drugs; Genes; Genetic Transcription; Glycoproteins; Gonadotrope Cell; Hematopoietic; Homeostasis; Hormones; Hypothalamic Hormones; Hypothalamic structure; In Vitro; Infertility; Malignant Neoplasms; Mediating; Messenger RNA; Molecular; N-terminal; Orphan; Pathway interactions; Phosphorylation; Phosphotransferases; Pituitary Gland; Pituitary Gonadotropins; Play; Post-Translational Protein Processing; Promoter Regions; Protein Kinase; Protein Overexpression; Proteins; Proto-Oncogene Proteins c-jun; Purpose; RNA-Binding Proteins; Range; Regulation; Role; Route; SF1; Signal Pathway; Signal Transduction; Site; Steroid biosynthesis; System; Technology; Testing; Transgenic Mice; Transgenic Organisms; Translations; WNT Signaling Pathway; cancer cell; extracellular; gonad function; hypothalamic pituitary gonadal axis; in vivo; jun Oncogene; malignant endocrine gland neoplasm; member; novel; novel therapeutics; promoter; receptor; receptor binding; recombinase; reproductive; reproductive function; sensor; therapeutic target

DESCRIPTION (provided by applicant): This application investigates three new and discrete aspects of the GnRH transcriptional network. Aim 1 should reveal to what extent post-transcriptional and post-translational mechanisms interface with GnRH regulated transcription of Egr1. While these mechanisms have been studied for IEGs in other systems, their role in gonadotropes remains unknown. We are convinced that the combination of post-transcriptional and post-translational contributions will provide a powerful one, two punch that ensures Egr1 mRNA and EGR1 protein reach maximally effective concentrations after transcriptional stimulation by GnRH. Aim 2 draws upon steadily emerging evidence, including our own, indicating that 2-catenin may be viewed as a new member of the GnRH signaling pathway that plays an instrumental role in regulating hormone stimulated expression of Jun mRNA and possibly Atf3 and Egr1 mRNA. Almost nothing is known about the signaling pathways GnRH uses to regulate transcription of Jun. Our approach addresses the role of 2-catenin as well as major pathway components such as PKC, PKA, and PI3K. Thus, Aim 2 is comprehensive and addresses a timely and important topic. The studies in Aim 3 address another novel feature of 2-catenin, namely its role as a required co-activator for SF1, certainly in acting permissively to allow Lhb to respond to transcriptional cues that flow from GnRH through Egr1. We suspect that the role of 2-catenin is broader and will extend to the other three signature genes that depend on SF1 for their expression. While Aims 1 and 2 are heavy on molecular detail and reliant on a gonadotrope cell line, Aim 3 uses transgenic technology to determine whether the requirement for 2-catenin and SF1 occurs in vivo and within the setting of a functional HPG axis. Most importantly, the transgenic approaches described in Aim 3 provide an exciting future direction that will be used to determine whether post-transcriptional and post-translational modifications uncovered for Egr1 have a significant impact when studied in vivo and in the context of a functional HPG axis. In short, we have charted an exciting new course that will deepen our mechanistic understanding of how GnRH controls gonadotrope homeostasis when signaling through a complex transcriptional network. Project Narrative: Normal reproductive function requires precise hypothalamic-gonadal control of the pituitary gonadotropins, LH and FSH. Too much or too little of either hormone disrupts gonadal function causing a spectrum of diseases ranging from infertility to endocrine cancer. This application focuses on GnRH, the hypothalamic hormone that signals through a cascade of protein kinases to regulate transcription, translation and ultimately secretion of LH and FSH from gonadotropes. Within this context, we consider how a tiered network of primary, secondary, and tertiary genes respond to the GnRH signal as well as contributions from components that act independently of GnRH. Completing these aims will deepen our understanding of the mechanistic coordination of gonadotrope gene expression required for maintaining reproductive homeostasis within the hypothalamic-pituitary-gonadal axis. Such an understanding is required for identifying new therapeutic targets and agents that can be used to either promote fertility or treat infertility and other endocrine disorders including hormone-dependent cancer.

描述(由申请人提供)：本申请调查了GnRH转录网络的三个新的和离散的方面。目的1揭示转录后和翻译后机制在多大程度上与GnRH调节的Egr1转录相互作用。虽然已经在其他系统中对IEGs的这些机制进行了研究，但它们在促性腺激素中的作用仍不清楚。我们相信，转录后和翻译后贡献的组合将提供强大的一、二重打击，确保在GnRH转录刺激后Egr1 mRNA和Egr1蛋白达到最大有效浓度。目的2利用包括我们自己的证据，表明2-catenin可能被视为GnRH信号通路中的一个新成员，在调节激素刺激的Jun mRNA以及可能的ATF3和Egr1 mRNA的表达中发挥重要作用。GnRH用来调节JUN转录的信号通路几乎一无所知。我们的方法研究了2-连环蛋白的作用以及主要的通路成分，如PKC，PKA和PI3K。因此，目标2是全面的，涉及一个及时而重要的主题。AIM 3中的研究解决了2-连环蛋白的另一个新特征，即它作为SF1所需的共激活因子的作用，当然是在允许LHB对从GnRH流经Egr1的转录线索做出反应方面。我们怀疑2-连环蛋白的作用更广泛，并将延伸到其他三个依赖于SF1表达的标志性基因。虽然目标1和2非常注重分子细节，并依赖于促性腺激素细胞系，但目标3使用转基因技术来确定对2-连环蛋白和SF1的需求是否发生在体内和功能HPG轴的设置内。最重要的是，Aim 3中描述的转基因方法提供了一个令人兴奋的未来方向，将用于确定在体内研究和在功能性HPG轴的背景下发现的Egr1的转录后和翻译后修饰是否会产生重大影响。简而言之，我们已经绘制了一条令人兴奋的新路线，这将加深我们对GnRH在通过复杂的转录网络发出信号时如何控制促性腺激素动态平衡的机械性理解。 项目简介：正常的生殖功能需要精确的下丘脑-性腺控制的脑下垂体促性腺激素、黄体生成素和卵泡刺激素。任何一种激素过多或过少都会扰乱性腺功能，导致从不孕不育到内分泌癌等一系列疾病。GnRH是一种下丘脑激素，通过一系列蛋白激酶发出信号，调节促性腺激素的转录、翻译和最终分泌促性腺激素和卵泡刺激素。在此背景下，我们考虑了初级、次级和三级基因的分层网络如何响应GnRH信号，以及独立于GnRH发挥作用的组件的贡献。完成这些目标将加深我们对维持下丘脑-垂体-性腺轴内生殖动态平衡所需的促性腺激素基因表达的机械协调的理解。要确定可用于促进生育或治疗不孕不育和包括激素依赖型癌症在内的其他内分泌疾病的新的治疗目标和药物，就需要这样的了解。