MUTATIONS OF G PROTEINS TARGETED TO HEART OF TRANSGENIC MICE

针对转基因小鼠心脏的 G 蛋白突变

• 批准号: 6110370
• 负责人: EVA J. NEER
• 金额: $ 29.06万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-01-01 至 1999-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6110370
• 关键词: G protein; adenylate cyclase; antisense nucleic acid; biological signal transduction; congestive heart failure; cyclic GMP; genetic models; genetically modified animals; heart function; laboratory mouse; messenger RNA; phospholipase C; second messengers; tissue /cell culture; ventricular hypertrophy

Receptors for many cardiac hormones and neurotransmitters are coupled to their effector enzymes or ion channels by a family of heterotrimeric GTP- binding proteins (G proteins) made up of alpha and betagamma subunits. These proteins act as critical control points for directing signals initiated at the cell surface to specific intracellular second messenger pathways. They are essential for normal cardiac function, and their derangement in pathological states including heart failure may contribute to abnormal responses of the heart to some agonists. Because the G proteins are structurally similar proteins whose functions sometimes overlap, it has been difficult to sort out the role of particular G proteins in complex cellular responses. Such a dissection of the signalling system is necessary before it would be possible to realize their potential usefulness as targets for pharmacological intervention in clinical states such as heart failure. The long-term goal of these studies is to define the role of individual G proteins in the normal and pathological function of cardiac cells. We propose to use genetic tools to create model systems in which we can study the biochemistry, cell biology and whole animal physiology of hearts with specific and reproducible alterations of signalling pathways. The strategy is to create transgenic models that express mutated alpha subunits only in the myocardium. These mutations will either cause the alpha subunits to be constitutively active or to act in a dominant negative fashion to inhibit the function of endogenous subunits. An alternative strategy will be to block G protein synthesis expressing antisense mRNA in the myocardium. These animals will provide a source of hearts all carrying the same modification that can be used to study the biochemistry of signal transduction, for analysis of the function of dissociated cultured cardiocytes, and for evaluation of the function of the whole organ both ex vivo and in vivo in the basal state and after induction of hypertrophy. These transgenic animals will make it possible eventually to define the contribution of particular G proteins to cardiac responses to those stresses that lead initially to hypertrophy and finally to failure.

许多心脏激素和神经递质的受体与 它们的效应酶或离子通道由异源三聚体 GTP- 家族控制 结合蛋白（G 蛋白）由 α 和 βamma 亚基组成。 这些蛋白质充当引导信号的关键控制点 从细胞表面起始到特定的细胞内第二信使 途径。 它们对于正常的心脏功能至关重要，并且 包括心力衰竭在内的病理状态紊乱可能会导致 心脏对某些激动剂的异常反应。 因为G 蛋白质是结构相似的蛋白质，其功能有时 重叠，很难理清特定 G 的作用 复杂细胞反应中的蛋白质。 这样的剖析 信号系统是必要的，然后才能实现它们 作为药物干预目标的潜在用途 心力衰竭等临床状态。 这些研究的长期目标是确定个体 G 的作用 心肌细胞正常和病理功能中的蛋白质。 我们 提议使用遗传工具来创建我们可以研究的模型系统 心脏的生物化学、细胞生物学和整个动物生理学 信号通路的特异性和可重复的改变。 策略 是创建转基因模型，仅在 心肌。 这些突变将导致 α 亚基 组成性活跃或以显性消极方式发挥作用以抑制 内源性亚基的功能。 另一种策略是 阻断心肌中表达反义 mRNA 的 G 蛋白合成。 这些动物将提供心脏的来源，所有这些动物都携带相同的心 可用于研究信号生物化学的修饰 转导，用于分析解离培养物的功能 心肌细胞，并用于评估整个器官的功能 体内以及在基础状态和诱导肥大后的体内。 这些转基因动物最终将有可能定义 特定 G 蛋白对心脏反应的贡献 最初导致肥大并最终导致失败的压力。