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Regulation of insulins by the Rhox5 homeobox gene supports spermatogenesis

Rhox5 同源框基因对胰岛素的调节支持精子发生

基本信息

批准号：
7614981
负责人：
JAMES Arthur MACLEAN
金额：
$ 7.23万
依托单位：
SOUTHERN ILLINOIS UNIVERSITY CARBONDALE
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-05-01 至 2010-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7614981
关键词：
15p Accounting Androgens Apoptosis Binding Biological Biological Models Biological Process Breeding Cell Communication Cell Cycle Regulation Cell Death Cell Line Cell Maturation Cell Survival Complex Consult Data Defect Development Elements Embryo Epithelial Cells Event Exhibits Failure Fertility Gene Expression Gene Targeting Genes Genetic Transcription Germ Cells Gonadal structure Homeobox Homeobox Genes Hormonal Human IGF1 gene Insulin Insulin-Like Growth Factor Receptor Knockout Mice Knowledge Laboratories Link Luciferases Mediating Metabolic Metabolism Microarray Analysis Molecular Morphology Mus Nuclear Hormone Receptors Nurses Organ Pancreas Patients Peroxisome Proliferator-Activated Receptors Physiology Plasmids Principal Investigator Process Proteins Regulation Regulatory Pathway Reporter Reproduction Reproductive system Research Response Elements Role Scientist Seminal fluid Somatic Cell Sperm Count Procedure Sperm Motility Spermatogenesis Staging Supporting Cell System Techniques Testis Tissues Transcription factor genes Transcriptional Activation Transfection Work X Chromosome adiponectin asthenospermia base cell growth regulation cell type cofactor design in vivo insulin signaling knockout gene leydig interstitial cell male mind control postnatal programs promoter reproductive reproductive development research study resistin response sertoli cell spermatogenic epithelium structure stem transcription factor

项目摘要

DESCRIPTION (provided by applicant): Homeobox genes encode transcription factors that control a wide variety of biological events. I recently identified a cluster of homeobox genes that are good candidates to regulate male reproductive development and physiology. Many of these reproductive homeobox (Rhox) genes are androgen regulated, and most are expressed in Sertoli cells (the nurse cells that support spermatogenesis), suggesting that they regulate the expression of somatic-cell gene products crucial for germ-cell development. Indeed, targeted deletion of one of these genes, Rhox5 (Pem), results in male subfertility, marked by increased germ-cell apoptosis and abnormal sperm motility. To begin to uncover the molecular events triggered by Rhox5 in Sertoli cells, I used microarray analysis to identify Rhox5-regulated genes, many of which encode proteins that have roles in metabolism, including insulin II (Ins2), resistin, and adiponectin, and the nuclear hormone receptor PPAR. Because insulin-like factors have recently been shown to support germ cell survival, I focused my initial studies on Rhox5 regulation of Ins2. Transient transfection of Rhox5 expression plasmids increased the activity of Ins2 promoter-driven luciferase reporter constructs. This was a breakthrough discovery for our laboratory, as no putative Rhox5-response elements had ever been discovered. Rhox5-mediated activation of the Ins2 promoter was Sertoli-cell specific, as it occurred in Sertoli cell lines and Sertoli cells purified from day 12 testes, but not cell lines derived from other tissues. This suggests that a Sertoli-specific cofactor is required for Rhox5-mediated transcriptional activation. In this application, I propose to characterize the mechanism by which Rhox5 regulates target genes in the testes. The experiments are designed to identify cofactors that work with Rhox5 to achieve cell-type specific expression of Rhox5-regulated genes. Because Rhox5 positively regulates metabolic factors that support germ cell survival, elucidation of the transcription control mechanism that leads to subfertility in Rhox5-null mice provides a useful model system for understanding human subfertility. Untreatable subfertility caused by poor semen quality accounts for 75% of patients consulting for fertility problems. This is due mainly to defects in sperm numbers (oligozoospermia) and sperm motility (asthenozoospermia). My proposed research strives to understand the mechanism by which the Rhox5 homeobox transcription factor controls the expression of genes that support male germ cell development. Mice which lack the Rhox5 gene exhibit abnormalities in sperm number, sperm motility, and breeding efficiency. Thus, the characterization of Rhox5-null mice may also be useful as a model system for understanding human fertility problems.

描述（由申请人提供）：同源框基因编码控制多种生物事件的转录因子。我最近发现了一组同源异型盒基因，它们是调节男性生殖发育和生理的良好候选基因。这些生殖同源异型盒（Rhox）基因中的许多是雄激素调节的，并且大多数在支持细胞（支持精子发生的滋养细胞）中表达，这表明它们调节对生殖细胞发育至关重要的体细胞基因产物的表达。事实上，有针对性地删除这些基因之一，Rhox 5（Pem），导致男性生育力低下，其特征是生殖细胞凋亡增加和精子活力异常。为了开始揭示Rhox 5在Sertoli细胞中引发的分子事件，我使用微阵列分析来鉴定Rhox 5调节的基因，其中许多基因编码在代谢中起作用的蛋白质，包括胰岛素II（Ins 2），GlucoN和脂联素，以及核激素受体PPAR。由于胰岛素样因子最近被证明支持生殖细胞存活，我将我的初步研究集中在Rhox 5对Ins 2的调节上。Rhox 5表达质粒的瞬时转染增加了Ins 2启动子驱动的荧光素酶报告构建体的活性。这对我们的实验室来说是一个突破性的发现，因为从来没有发现过假定的Rhox 5反应元件。Rhox 5介导的Ins 2启动子的激活是支持细胞特异性的，因为它发生在支持细胞系和从第12天睾丸纯化的支持细胞中，而不是来自其他组织的细胞系。这表明，Sertoli特异性辅因子是Rhox 5介导的转录激活所必需的。在本申请中，我建议描述Rhox 5在睾丸中调节靶基因的机制。这些实验旨在鉴定与Rhox 5一起工作以实现Rhox 5调节基因的细胞类型特异性表达的辅因子。由于Rhox 5正调控支持生殖细胞存活的代谢因子，因此阐明导致Rhox 5缺失小鼠生育力低下的转录控制机制为理解人类生育力低下提供了有用的模型系统。由于精液质量差而导致的无法治疗的生育力低下占咨询生育问题的患者的75%。这主要是由于精子数量（少精子症）和精子活力（弱精子症）的缺陷。我提出的研究旨在了解Rhox 5同源框转录因子控制支持男性生殖细胞发育的基因表达的机制。缺乏Rhox 5基因的小鼠表现出精子数量、精子活力和繁殖效率的异常。因此，Rhox 5-null小鼠的表征也可以用作理解人类生育问题的模型系统。