TRANSCRIPTIONAL CONTROL OF VACUOLAR H+-ATPASE EXPRESSION

液泡H-ATP酶表达的转录控制

• 批准号: 2623984
• 负责人: BETH S. LEE
• 金额: $ 14.51万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-01-01 至 2001-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2623984
• 关键词: adenosinetriphosphatase; affinity chromatography; gene expression; genetic regulatory element; genetic transcription; genetically modified animals; hydrogen ions; hydrogen transport; in situ hybridization; laboratory mouse; laboratory rat; membrane transport proteins; radiotracer; renal tubular transport; tissue /cell culture; transcription factor; vesicle /vacuole

Plasma membrane vacuolar H+ATPases (V-ATPases) have an essential role in renal bicarbonate transport, osteoclast bone resorption, and macrophage pH homeostasis. These transporters account for one third of proximal tubule bicarbonate reabsorption, and for the majority of H+ transport in the collecting duct, where fine control of acid secretion occurs. V-ATPases on the ruffled membranes of osteoclasts are crucial for creation of the acidic microenvironments required for bone resorption, and on macrophage plasma membranes are essential for intracellular pH regulation in acidic environments such as abscessed tissue. Vacuolar H+ATPases are present at low densities in the vacuolar system of all eukaryotic cells. In specialized proton-secreting cells such as the proximal tubule cell, intercalated cell, osteoclast and macrophage, vacuolar H+ATPase expression is greatly amplified, and the high enzyme density on the plasma membrane confers the capacity for cellular proton secretion. The goal of this proposal is to identify mechanisms responsible for amplified H+ATPase expression in specific cell types by analyzing the control of the vacuolar H+-ATPase subunit transcription. The specific aims are: 1a) to isolate and characterize a potentially novel transcription factor that regulates vacuolar H+-ATPase expression in cells of the monocytic lineage; 1b) to determine the tissue distribution and expression patterns of this factor; 2) to define cis- acting elements required for high levels of vacuolar H+-ATPase expression in the proximal tubule of the kidney; and 3) to verify the role of vacuolar H+-ATPase promoter elements through construction of a transgenic mouse model. These studies will aid in understanding the genetic regulatory elements that are required for terminal differentiation of specialized proton- transporting cells. The information obtained may also provide new insights on mechanisms of abnormal osteoclast function in bone disease, macrophage malfunction in immunodeficiency disorders, and the disorders of urinary acidification common in renal disease.

质膜液泡H+-ATPase(V-ATPase)具有重要作用 在肾重碳酸盐转运、破骨细胞骨吸收和 巨噬细胞pH动态平衡。这些传送器占到了三分之一 近端小管重吸收碳酸氢盐，并对大部分H+ 在收集管中传输，在那里精细控制酸的分泌 发生。破骨细胞皱褶膜上的V-ATPase是至关重要的 用于创造骨骼所需的酸性微环境 吸收和在巨噬细胞质膜上是必不可少的 酸性环境中的细胞内pH调节，如脓肿 组织。 液泡H+-ATPase在液泡系统中以低密度存在 在所有真核细胞中。在特殊的质子分泌细胞中，如 近端小管细胞、间质细胞、破骨细胞和巨噬细胞， 液泡H+ATPase表达大大扩增，高酶 质膜上的密度赋予细胞质子的能力 分泌物。 这项提案的目标是确定负责 通过分析H+ATPase在特定细胞类型中的扩增表达 液泡H+-ATPase亚单位转录的调控。具体的 目标是：1A)分离和描述一个潜在的新奇事物 调节空泡H+-ATPase表达的转录因子 单核细胞系的细胞；1b)确定组织 该因子的分布和表达模式；2)定义顺式- 高水平液泡H+-ATPase所需的作用元件 在肾脏近端小管中的表达；以及3)验证 液泡H+-ATPase启动子元件通过构建 转基因小鼠模型。 这些研究将有助于理解基因调控元件。 是专门化质子末端分化所必需的- 运输细胞。所获得的信息还可以提供新的 破骨细胞功能异常在骨病中的作用机制， 免疫缺陷疾病中的巨噬细胞功能障碍及其相关疾病 肾脏疾病中常见的尿酸中毒。