Regulation of the Na/K Pump by RNA Editing

RNA 编辑对 Na/K 泵的调节

• 批准号: 7029764
• 负责人: JOSHUA J.C. ROSENTHAL
• 金额: $ 34.85万
• 依托单位: UNIVERSITY OF PUERTO RICO MED SCIENCES
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-12-08 至 2009-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7029764
• 关键词: Puerto Rico; Xenopus; adenine deaminase; adenosine; alternatives to animals in research; amination; biophysics; chemical structure function; complementary DNA; cooperative study; gene mutation; genetic mapping; inosine; membrane permeability; messenger RNA; minority institution research support; molecular cloning; molecular genetics; molecular site; neurobiology; neurogenetics; neuroregulation; nucleic acid sequence; posttranscriptional RNA processing; site directed mutagenesis; sodium potassium exchanging ATPase; squid

The long term objective of this work is to understand, at a molecular and biophysical level, how RNA editing regulates ion channels and transporters. RNA editing by adenosine deamination is a posttranscriptional process that is essential for proper nervous system function. Although many mRNA substrates have been shown to be edited by this mechanism, very little is known about the functional consequences of these modifications. This proposal focuses on the Na/K pump as a model membrane protein because it plays a central role in the regulation of ion homeostasis. The enzymatic conversion of adenosine to inosine (A -> I) in pre- mRNAs allows multiple protein products from a single gene, thereby extending the genomic capability of an organism. These conversions are not random, but are targeted to functionally important domains within the protein. For example, in the GluRB subunit of the glutamate-gated ion channel, important for fast excitatory synaptic transmission in the central nervous system, editing underlies the conversion of Q to R in the channel's pore. This change, which is essential for survival, renders the receptor impermeable to calcium ions. Edited substrates are identified by comparing genomic and cDNA sequences for the same gene. This process is greatly simplified in squid where editing is extensive. This proposal takes advantage of high level editing in squid to identify mutations that are functionally relevant.

这项工作的长期目标是在分子和生物物理水平上理解RNA编辑如何调节离子通道和转运蛋白。腺苷脱氨酸编辑的RNA是一个 转录后过程对于适当的神经系统功能至关重要。尽管已经证明许多mRNA底物是通过这种机制编辑的，但对这些修饰的功能后果知之甚少。该提案的重点是Na/k泵作为模型膜蛋白，因为它在离子稳态调节中起着核心作用。 在Pre -mRNA中，腺苷转化为肌苷（A-> i）允许多种蛋白 从单个基因的产物，从而扩展了生物体的基因组能力。这些 转化不是随机的，而是针对蛋白质中功能上重要的结构域。例如，在谷氨酸门控离子通道的Glurb亚基中，对于中枢神经系统中的快速兴奋性突触传播至关重要，编辑是该通道孔中Q转换为R的基础。这对于生存至关重要的变化使受体不渗透钙离子。通过比较同一基因的基因组和cDNA序列来鉴定编辑的底物。在编辑广泛的鱿鱼中，大大简化了此过程。该建议利用鱿鱼中的高级编辑来识别功能相关的突变。