Regulation of vitamin A synthesis from carotenoids

类胡萝卜素合成维生素 A 的调节

• 批准号: 7025054
• 负责人: JISUN PAIK
• 金额: $ 20.43万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-15 至 2008-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7025054
• 关键词: SDS polyacrylamide gel electrophoresis; alcohol dehydrogenase; carotene; carotenoids; chemical cleavage; enzyme activity; gene expression; genetic regulation; genetically modified animals; high performance liquid chromatography; intestines; laboratory mouse; liver; northern blottings; protein protein interaction; retinoid binding proteins; retinoids; transcription factor; vitamin biosynthesis; vitamin metabolism; western blottings

DESCRIPTION (provided by applicant): All higher animals, including humans, must obtain vitamin A from the diet since they lack the ability to synthesize it de novo. Ultimately all vitamin A is formed from provitamin A carotenoids. The conversion process of provitamin A carotenoids to vitamin A has been studied for more than 4 decades although the cloning and purification of the enzyme responsible for the cleavage of provitamin A carotenoids to vitamin A were only recently accomplished when we and others cloned and characterized both mouse and human carotene cleavage enzyme (CCE). CCE was found to be ubiquitously expressed throughout the body and thus likely plays a general role in providing vitamin A to target tissues. The goal of our proposed studies is to understand the regulatory mechanisms controlling provitamin A conversion to vitamin A in intestine and liver. Two aspects of this regulation will be explored. First, we will examine the regulation of CCE activity by other proteins, possibly through direct protein-protein interactions. Cellular retinol-binding proteins (CRBPs) are known to interact with retinal, the product of carotene cleavage within cells. The effects of CRBPs on CCE activity will be examined using both in vitro and in vivo techniques. In addition, we will explore the direct down-stream enzyme to CCE, retinal reductase. We have identified two known short chain dehydrogenase/reductases, retSDR and RalR1, as candidate intestinal retinal reductases. The role of these two enzymes on retinol production from beta-carotene will be explored in depth. Finally, we will investigate the transcriptional regulation of hCCE expression. Here, we propose to examine the promoter of the human CCE gene to identify cis-regulatory elements and transcription factors that bind to these regulatory sequences in this gene. These data will provide insights into regulation of the CCE gene in humans. Taken together these studies will provide comprehensive understanding of CCE activity in two major tissue sites, intestine and liver.

描述（由申请人提供）：所有高等动物，包括人类，都必须从饮食中获得维生素A，因为它们缺乏合成从头开始的能力。最终，所有维生素A均由类胡萝卜素A形成。普罗维生胺A类胡萝卜素对维生素A的转化过程已被研究了40多年，尽管酶的克隆和纯化负责导致类胡萝卜素A对维生素A的切割的裂解，直到我们最近才在我们和其他小鼠串起和表征小鼠时才能完成和人类胡萝卜素裂解酶（CCE）。发现CCE在整个人体中无处不在表达，因此可能在为靶组织提供维生素A提供一般作用。我们提出的研究的目的是了解控制普罗维生胺A转化为肠道和肝脏中维生素A的调节机制。将探讨该法规的两个方面。首先，我们将通过直接蛋白质 - 蛋白质相互作用来检查其他蛋白质对CCE活性的调节。已知细胞视黄醇结合蛋白（CRBP）与视网膜相互作用，视网膜是细胞内胡萝卜素裂解的产物。将使用体外和体内技术研究CRBP对CCE活性的影响。此外，我们将探索直接下游酶至CCE，视网膜还原酶。我们已经确定了两个已知的短链脱氢酶/还原酶RETSDR和RALR1为候选肠道视网膜还原酶。这两种酶在β-胡萝卜素产生视黄醇中的作用将深入探讨。最后，我们将研究HCCE表达的转录调控。在这里，我们建议检查人类CCE基因的启动子，以识别与该基因中这些调节序列结合的顺式调节元件和转录因子。这些数据将为人类中CCE基因的调节提供见解。综上所述，这些研究将提供对两个主要组织部位（肠道和肝脏）中CCE活性的全面理解。