TRANSCRIPTIONAL CONTROL OF VACUOLAR H+-ATPASE EXPRESSION

液泡H-ATP酶表达的转录控制

• 批准号: 2634309
• 负责人: BETH S. LEE
• 金额: $ 13.7万
• 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/2634309
• 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+ATP 酶（V-ATP 酶）具有重要作用 肾脏碳酸氢盐转运、破骨细胞骨吸收和 巨噬细胞 pH 稳态。这些运输商占了三分之一 近曲小管碳酸氢盐重吸收，并且对于大多数 H+ 在集合管中运输，精细控制酸分泌 发生。破骨细胞皱褶膜上的 V-ATP 酶至关重要 用于创建骨骼所需的酸性微环境 重吸收和巨噬细胞质膜对于 酸性环境（如脓肿）中的细胞内 pH 调节 组织。 液泡 H+ATP 酶在液泡系统中以低密度存在 所有真核细胞。在专门的质子分泌细胞中，例如 近曲小管细胞、闰细胞、破骨细胞和巨噬细胞， 液泡H+ATP酶表达大大放大，酶量高 质膜上的密度赋予细胞质子的能力 分泌。 该提案的目标是确定负责的机制 通过分析特定细胞类型中 H+ATPase 的表达情况 液泡H+-ATP酶亚基转录的控制。具体的 目标是： 1a）分离并表征潜在的新颖性 调节液泡 H+-ATPase 表达的转录因子 单核细胞谱系的细胞； 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+-ATP 酶所需的作用元件 在肾近曲小管中表达； 3) 验证 通过构建液泡H+-ATP酶启动子元件的作用 转基因小鼠模型。 这些研究将有助于了解遗传调控元件 特殊质子的终末分化所需的 运输细胞。获得的信息还可能提供新的 对骨病中破骨细胞功能异常机制的见解， 免疫缺陷疾病中的巨噬细胞功能障碍，以及这些疾病 肾脏疾病中常见的尿酸化。