The Role of AP-1 in the Gonadotrope

AP-1 在促性腺激素中的作用

• 批准号: 8241644
• 负责人: DJURDJICA COSS
• 金额: $ 30.79万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-04-01 至 2013-02-01
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8241644
• 关键词: Address; Affect; Animals; Anterior Pituitary Gland; Binding; Biological Assay; Cell Culture Techniques; DNA Binding; Development; Embryo; FOS gene; Female; Fertility; Follicle Stimulating Hormone; Functional disorder; Gametogenesis; Gene Expression; Gene Expression Regulation; Genes; Genetic Transcription; Genetically Modified Animals; Goals; Gonadal structure; Gonadotrope Cell; Gonadotropin Hormone Releasing Hormone; Gonadotropins; Health; Heterodimerization; Hormones; Hypothalamic structure; Immediate-Early Genes; JUN gene; Knock-out; Lead; Luteinizing Hormone; Mammals; Mediating; Modeling; Molecular; Mus; Ovarian Follicle; Phenotype; Physiology; Pituitary Gland; Population; Protein Isoforms; Proteins; Regulation; Reproduction; Reproductive History; Reproductive system; Role; Steroid biosynthesis; System; Technology; Transcription Factor AP-1; Translations; Work; chromatin immunoprecipitation; fitness; hormone regulation; in utero; in vivo; insight; novel strategies; overexpression; promoter; protein degradation; reproductive function; transcription factor

DESCRIPTION (provided by applicant): Gametogenesis in females is controlled by follicle-stimulating hormone (FSH) from the pituitary, which is, in turn, regulated by gonadotropin-releasing hormone (GnRH) from the hypothalamus. GnRH regulates FSH synthesis through induction of the immediate early gene, c-Fos, which, upon heterodimerization with c-Jun, creates an AP-1 transcription factor that binds the promoter of the FSH 2-subunit gene. The overall goal of this application is to ascertain the mechanism of GnRH induction of c-Fos and to elucidate the role of AP-1 in the gonadotrope in vivo. AP-1 is the only factor known to be involved in the induction of the FSH 2-subunit gene by GnRH. c-Fos, the most highly GnRH-induced gene in the gonadotrope, is the most regulated AP-1 isoform, while c-Jun expression varies less with hormone treatment. The molecular mechanism of c-Fos induction by GnRH in the gonadotrope cell is not known. Neither has a role for AP-1 in reproduction in vivo been determined. Herein, I will utilize novel approaches to delineate the mechanisms underlying the regulation of c- Fos expression by GnRH. In the first aim, I will determine the molecular mechanism of c-Fos induction by GnRH. In the second aim, I will determine the regulation of protein stability and degradation, since c-Fos is an immediate-early gene with a very unstable message and labile protein, and its cellular concentration is controlled on the level of turnover, as much as on the level of expression. In the third aim of this proposal, I will determine the function of AP-1 in reproduction in vivo with the use of genetically modified animals. First, I will assess reproductive function and gonadotropin expression in c-Fos deficient animals and then, as complementary approach, use mice that lack c-Jun specifically in the pituitary gonadotrope. Jun isoforms are obligatory heterodimeric partners for Fos isoforms, whose interaction creates an AP-1 transcription factor that binds DNA. c-Jun, in particular, is essential for development, since knock-out animals die in utero, and with the use of CRE-lox system, I will analyze the function of c-Jun in gonadotrope in vivo. Results obtained from these studies will make substantial contributions to our understanding of the molecular mechanisms that affect gene expression in the gonadotrope and provide insight into the physiology and pathophysiology of the mammalian reproductive system. I propose to expand our understanding of molecular mechanisms of GnRH induction of c- Fos gene in the gonadotrope in a cell culture model, which will lead to a better understanding of GnRH regulation of gene expression in the pituitary, and the function of AP-1 in vivo, utilizing genetically modified mice. PUBLIC HEALTH RELEVANCE: Fertility in mammals is regulated primarily by gonadotropin-releasing hormone effect on the gonadotrope cell population in the pituitary gland, through modulation of gonadotropin gene expression and secretion. Gonadotropins, follicle-stimulating hormone and luteinizing hormone, work on the gonads to stimulate gametogenesis and steroidogenesis. This proposal will address the molecular mechanism of gene regulation by GnRH in the gonadotrope cell.

描述（由申请人提供）：女性的配子发生由垂体的促卵泡激素（FSH）控制，而促卵泡激素又由下丘脑的促性腺激素释放激素（GnRH）调节。 GnRH 通过诱导立即早期基因 c-Fos 来调节 FSH 合成，c-Fos 与 c-Jun 异二聚化后，产生与 FSH 2 亚基基因启动子结合的 AP-1 转录因子。本申请的总体目标是确定 GnRH 诱导 c-Fos 的机制并阐明 AP-1 在体内促性腺激素中的作用。 AP-1 是唯一已知参与 GnRH 诱导 FSH 2 亚基基因的因子。 c-Fos 是促性腺激素中 GnRH 诱导程度最高的基因，是受调节程度最高的 AP-1 亚型，而 c-Jun 表达随激素治疗的变化较小。促性腺细胞中 GnRH 诱导 c-Fos 的分子机制尚不清楚。 AP-1 在体内繁殖中的作用均未确定。在此，我将利用新方法来描述 GnRH 调节 c-Fos 表达的机制。第一个目标是确定 GnRH 诱导 c-Fos 的分子机制。在第二个目标中，我将确定蛋白质稳定性和降解的调节，因为 c-Fos 是一种立即早期基因，具有非常不稳定的信息和不稳定的蛋白质，并且其细胞浓度受周转水平控制，尽可能多在表达层面上。在本提案的第三个目标中，我将利用转基因动物来确定 AP-1 在体内繁殖中的功能。首先，我将评估 c-Fos 缺陷动物的生殖功能和促性腺激素表达，然后作为补充方法，使用垂体促性腺激素中专门缺乏 c-Jun 的小鼠。 Jun 异构体是 Fos 异构体的必需异二聚体伙伴，它们的相互作用产生了结合 DNA 的 AP-1 转录因子。尤其是c-Jun对于发育至关重要，因为基因敲除动物会在子宫内死亡，通过使用CRE-lox系统，我将分析c-Jun在体内促性腺激素中的功能。从这些研究中获得的结果将为我们理解影响促性腺激素基因表达的分子机制做出重大贡献，并提供对哺乳动物生殖系统的生理学和病理生理学的深入了解。我建议在细胞培养模型中扩大我们对GnRH诱导促性腺激素c-Fos基因的分子机制的理解，这将有助于更好地理解GnRH对垂体基因表达的调节以及AP-1的功能在体内，利用转基因小鼠。公共健康相关性：哺乳动物的生育力主要是通过促性腺激素释放激素对垂体促性腺细胞群的作用来调节的，通过调节促性腺激素基因表达和分泌来调节。促性腺激素、促卵泡激素和黄体生成素作用于性腺，刺激配子发生和类固醇生成。该提案将解决促性腺激素细胞中 GnRH 基因调控的分子机制。