Role of Dicer in Gonadotrope and Reproductive Function

描述(申请人提供)：促性腺激素合成和分泌异二聚体糖蛋白黄体生成素和卵泡刺激素。 生殖功能。共同的α亚基(CGA)和激素特异性的β亚基(LHB和FSHB)的编码基因受下丘脑促性腺激素释放激素、类固醇和性腺肽、抑制素和激活素的协调调节。虽然在促性腺激素β亚基的转录调控方面已经积累了丰富的知识，但这些基因的转录后机制尚不清楚。近年来，作为一种核糖核酸内切酶III，DICER产生的miRNAs(MiRNAs)已成为基因表达、mRNA稳定性和蛋白质合成的关键调控因子。缺乏关于调节促性腺激素和生殖功能的miRNAs的知识。我们的长期研究目标是阐明体内调节促性腺激素合成和分泌的机制。中心假说是DICER是促性腺激素miRNA生物发生的关键因子，并在促性腺激素合成和生殖功能中发挥重要作用。在具体目标1中，我们将通过cre-lox技术有条件地删除促性腺激素中唯一的Dier，并分析促性腺激素的合成和分泌。此外，我们将使用新的小鼠品系，其中促性腺激素在正常或激活素受体II(Acvr2)缺失的遗传背景上用GFP标记。将通过基于GFP荧光的细胞分选从这些小鼠中分离出纯的促性腺激素群体，并鉴定受Acvr2调控的miRNAs。在特定的目标2中，将确定促性腺激素因Dier缺失而发生变化的继发性生殖表型。这些研究将提供关于促性腺激素中依赖于DICER的miRNAs的新知识，并确定促性腺激素分泌的新的转录后机制。阐明促性腺激素的分泌机制是生殖生理学的基础，并为诊断和治疗促性腺激素依赖性生育/不育疾病提供长期的临床益处。 与公共健康相关：我们的研究应该提供新的知识，说明DICER如何产生称为microRNAs的小RNAs，调节脑下垂体合成和分泌卵泡刺激素(FSH)和黄体生成素(LH)。阐明FSH和黄体生成素的分泌机制是生殖生理学的基础，并为诊断和治疗FSH依赖型生育/不育疾病提供临床益处。其中一些包括过度刺激综合征、闭经和睾丸缺陷。

DESCRIPTION (provided by applicant): Gonadotropes synthesize and secrete heterodimeric glycoproteins luteinizing hormone (LH) and follicle stimulating hormone (FSH) that are critical for reproductive function. The genes encoding the common alpha subunit (Cga) and the hormone-specific beta subunits (Lhb and Fshb) are coordinately regulated by hypothalamic gonadotropin-releasing hormone, steroids and gonadal peptides, inhibin and activin. Although a wealth of knowledge has accumulated on transcriptional control of gonadotropin beta subunits, post- transcriptional mechanisms of these genes are unknown. Recently, micro RNAs (miRNAs) produced by Dicer, an RNA endonuclease III, have emerged as key regulators of gene expression, mRNA stability and protein synthesis. Knowledge on miRNAs that regulate gonadotrope and consequently reproductive function is lacking. Our long-term research goal is to elucidate the in vivo mechanisms that regulate gonadotropin synthesis and secretion. The central hypothesis is that Dicer is a key factor in miRNA biogenesis in gonadotropes and plays essential roles in gonadotropin synthesis and consequently reproductive function. In Specific Aim 1, we will conditionally delete Dicer exclusively in gonadotropes by cre-lox technology and analyze gonadotropin synthesis and secretion. Additionally, we will use novel mouse strains, in which gonadotropes are labeled with GFP on a normal or activin receptor-II (Acvr2) null genetic background. Pure populations of gonadotropes will be isolated from these mice by cell sorting based on GFP fluorescence and miRNAs regulated by Acvr2 identified. In Specific Aim 2, reproductive phenotypes secondary to changes in gonadotropins as a result of Dicer deletion in gonadotropes will be determined. These studies should provide new knowledge on Dicer - dependent miRNAs in gonadotropes and identify novel post-transcriptional mechanisms for gonadotropin secretion. Delineation of mechanisms of gonadotropin secretion is fundamental to physiology of reproduction and offers long-term clinical benefits of diagnosing and treating gonadotropin-dependent fertility/infertility disorders. PUBLIC HEALTH RELEVANCE: Our studies should provide new knowledge on how Dicer that produces small RNAs called micro RNAs regulates synthesis and secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from pituitary gland. Delineation of mechanisms of FSH and LH secretion is fundamental to physiology of reproduction and offers clinical benefits of diagnosing and treating FSH-dependent fertility/infertility disorders. Some of these include hyperstimulation syndromes, amenorrhea and testicular defects.