CYCLIC NUCLEOTIDE PHOSPHODIESTERASES IN OLFACTION

嗅觉中的环核苷酸磷酸二酯酶

• 批准号: 2770234
• 负责人: JAMES A. CHERRY
• 金额: $ 12.72万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-09-15 至 2000-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2770234
• 关键词: 3'5' cyclic nucleotide phosphodiesterase; RNase protection assay; behavior test; biological signal transduction; calmodulin; chemoreceptors; cyclic AMP; developmental genetics; developmental neurobiology; embryo /fetus culture; experimental brain lesion; gene expression; gene targeting; immunocytochemistry; in situ hybridization; laboratory mouse; mammalian embryology; molecular cloning; nervous system regeneration; neurogenesis; neurogenetics; olfactions; olfactory lobe; respiratory epithelium; restriction mapping; sensory discrimination

The long-range goals of this research program are to define the fundamental cellular mechanisms involved in olfactory perception. A critical and active component of the molecular pathway underlying odorant transduction is the second messenger molecule cAMP, which has been shown to increase rapidly in olfactory sensory neurons upon odor stimulation. The focus of this proposal is on the enzymes that degrade these molecules- - cyclic nucleotide phosphodiesterases (PDEs)-- and are therefore well- situated to act as modulators of the olfactory signals that are ultimately transmitted to the brain. In mammals one of these enzymes is a homolog of the Drosophila dunce gene, which codes for a cAMP-specific PDE. This gene has recently been cloned in the mouse and shown to be abundantly and preferentially expressed in olfactory sensory neurons. A series of studies are proposed to extend this initial discovery. First, the developmental onset of the dunce homolog, called mPDE2, will be established during early formation of the olfactory system. Regulation of this enzyme will then be examined during degeneration and subsequent regeneration of the olfactory mucosa following unilateral removal of the olfactory bulb, which is the target of the sensory neuron axons. Techniques in molecular genetics will then be used to begin addressing basic questions concerning the role of this PDE in olfaction. First, the gene structure of mPDE2 will be studied, including investigations into the protein and/or mRNA heterogeneity in olfactory tissue. Then the mPDE2 gene will be disrupted, or knocked out, using homologous recombination in embryonic stem cells. Once the mice lacking a functional mPDE2 gene are obtained they will be thoroughly analyzed morphologically, physiologically, and behaviorally for any phenotypic abnormalities, particularly with respect to potential deficiencies associated with olfactory function. Finally, to address more completely the issue of PDE function in olfaction, it will be necessary to characterize the other major PDE found in sensory neurons-- a Ca2+ and calmodulin-activatible PDE, or CaM PDE. Therefore, identification of the CaM PDEs expressed in the olfactory system by molecular cloning is proposed. It is expected that these experiments will contribute important information about the role of cyclic nucleotide PDEs in olfaction.

该研究计划的远程目标是定义 涉及嗅觉的基本细胞机制。 一个 分子途径的关键和活性成分 转导是第二个使者分子训练营，已显示 在气味刺激下，嗅觉感觉神经元中迅速增加。 该提案的重点是降解这些分子的酶 - 环状核苷酸磷酸二酯酶（PDES），因此非常好 位于最终是嗅觉信号的调节器 传输到大脑。 在哺乳动物中，这些酶之一是 果蝇Dunce基因编码为营地特异性PDE。 这个基因 最近被克隆到鼠标中，显示出丰富的 优先在嗅觉感觉神经元中表达。 一系列 提出了研究以扩展此最初发现。 首先， Dunce同源物的发展发作，称为MPDE2，将是 在嗅觉系统的早期形成期间建立。 调节 然后，将在变性和随后检查该酶 单方面去除后嗅觉粘膜的再生 嗅球，这是感觉神经元轴突的靶标。 然后将使用分子遗传学技术开始解决 有关该PDE在嗅觉中的作用的基本问题。 首先， 将研究MPDE2的基因结构，包括研究 嗅觉组织中的蛋白质和/或mRNA异质性。 然后是mpde2 基因将使用同源重组而被破坏或淘汰 胚胎干细胞。 一旦缺乏功能性MPDE2基因的小鼠是 获得的它们将在形态上进行彻底分析， 在生理和行为上，对于任何表型异常， 特别是关于与之相关的潜在缺陷 嗅觉功能。 最后，更完全解决PDE的问题 在嗅觉中的功能，有必要表征另一个 在感觉神经元中发现的主要PDE- Ca2+和钙调蛋白活活 PDE或CAM PDE。 因此，识别以 提出了通过分子克隆的嗅觉系统。 预计 这些实验将为有关 环状核苷酸PDE在嗅觉中的作用。