N-acetylglutamate Synthase: Structure, Function & Defects

描述(由申请人提供)：这是一份针对追回法案资金通知编号NOT-OD-09-058的竞争性修订申请。Over Goal的母项目是探索N-乙酰谷氨酸合成酶(NAGS)的生物学、生化和病理生理学，NAG是一种产生同源辅因子N-乙酰谷氨酸(NAG)的酶，NAG是尿失禁过程中必不可少的变构激活剂。此修订应用程序向父项目添加了两个新目标。1.建立NAGS缺乏症基因敲除小鼠，鉴定其表型，探讨其作为条件性高氨血症模型的应用。2.通过比较N-氨基甲酰谷氨酸(NCG)处理的KoNAGS小鼠和野生型仔鼠的氮代谢，在NAGS/CPSI水平上分离和研究尿失禁的体内调控。除了这些将在两年内完成的新目标外，这项计划还将在长期内加强现有的两个目标，即研究精氨酸对NAGS功能的影响，以及NAGS缺乏症患者自然发生的突变的影响。在这个修订的项目中，我们将开发、研究并向研究界提供一种新的“可滴定的高氨血症小鼠模型”。这只基因敲除的NAGS小鼠将被NCG救治，并在停用这种辅因子类似物后发展为高氨血症。我们将确定在体内的氮平衡和代谢之间的差异，在NAGS“调节剥夺”的KoNAGS小鼠与自然调节的野生型窝产仔和非NCG的对照。这些研究将同时使用基因表达和蛋白质图谱方法，并将首次在体内“分离”NAG对尿失禁的调节作用。这个项目将通过为我们的小组和其他研究高氨血症的研究人员提供一个新的活体研究工具来提高父母赠款的速度和质量。此外，通过向全国各地的其他研究人员提供Kongas鼠标模型，加强他们的研究并促进创造新的就业机会，利用该项目对经济的贡献。 与公共健康相关：这个项目致力于研究一种重要的基因和蛋白质(NAG)，它决定了我们从身体中排出多少氮。知道这一点很重要，因为肝病的主要问题之一是无法消除有毒的氮(氨)，它可以毒害大脑。我们将研究一只没有NAG的工程小鼠，以使我们更好地理解这一系统以及它是如何被调控的。该项目的结果可能会为氨水平升高开发新的治疗方法，以保护大脑免受其毒性影响。

DESCRIPTION (provided by applicant): This is a Competitive Revision Application in response to the Recovery Act Funds Notice Number NOT-OD-09- 058. The parent project over goal is to explore the biology, biochemistry and pathophysiology of N- acetylglutamate synthase (NAGS) is an enzyme that produces the cognate cofactor N-acetylglutamate (NAG), an essential allosteric activator in ureagenesis. This revision application adds two new aims to the parent project. 1. To develop a knockout mouse for NAGS deficiency, characterize its phenotype, and explore its use as a conditional hyperammonemia model. 2. To "isolate" and study the in vivo regulation of ureagenesis specifically at the level of NAGS/CPSI by comparing nitrogen metabolism in N-carbamylglutamate (NCG) treated koNAGS mouse vs. wild type littermates. In addition to these new aims to be completed in two years, this project will enhance in the long term two of the existing aims that study the arginine effects on NAGS function and the effect of naturally-occurring mutations in patients with NAGS deficiency. In this revised project, we will develop, study and make available to the research community a novel "titratable mouse model of hyperammonemia. This knockout NAGS mouse will be rescued with NCG and will develop hyperammonemia upon withdrawal of this cofactor analog. We will determine the in vivo differences between nitrogen balance and metabolism in the NAGS "regulation-deprived" koNAGS mice rescued with NCG vs. the naturally-regulated wild type littermates on and off NCG. These studies will use both gene expression and protein profiles methods and will allow for the first time to "isolate" in vivo the regulatory effects of NAGS on ureagenesis. This project will enhance the pace and quality of the parent grant by providing a new tool for in vivo investigations for our group and other investigators studying hyperammonemia. In addition, The contribution of this project to the economy is leveraged by making the koNGAS mouse model available to othr investigators across the country, enhancing their research and promoting new job creation. PUBLIC HEALTH RELEVANCE: This project is dedicated to the investigation of an important gene and protein (NAGS) that determined how much nitrogen we eliminate from our bodies. It is important to know this since one of the main problem in liver disease is the inability to eliminate toxic nitrogen (ammonia) which can poison the brain. We will study an engineered mouse that does not posses NAGS to allow us to better understand this system and how it is regulated. The results from this project could allow the development of new treatments for elevated ammonia levels to protect the brain from its toxic effects.