APP mRNA Dysregulation and Alzheimer's Disease

描述（由申请人提供）：越来越多的共识是，从淀粉样前体蛋白（APP）裂解的β A4肽的不溶性沉积物的沉积是AD病理生物学的核心。APP和β A4的过度产生可由过量的APP mRNA引起，如在唐氏综合征（DS）患者、APP纯合转基因动物和迟发型AD患者的子集中。我们已经表明，APP mRNA丰度和下游APP合成的转录后控制至少两个，3'非翻译区调控元件。29个碱基的元件（29 be）在终止密码子的3'端有200个碱基，使APP mRNA不稳定。最近，我们发现APP mRNA含有一个迄今未知的稳定元件，位于终止密码子的3'端，并从终止密码子延伸50个碱基（50 sc元件或50 sce）。该区域独特地存在于APP mRNA中。至少有一种细胞质蛋白与50 sce特异性相互作用。在多个细胞系和原代细胞中检测到结合活性，表明广泛分布。在转染细胞中，50 sc元件的缺失使APP mRNA降解加速达8倍，并使APP产生减少大约相同的量。内源性，野生型APP mRNA和蛋白质显着减少SH-SY-5 Y细胞转染50 sce反义寡核苷酸或诱饵mRNA含有一个拷贝的正义50 sce。因此，我们假设50 sce也调节APP mRNA衰减的速率，并通过与细胞质结合蛋白的特异性相互作用来实现。我们还推测，干扰50 sc元件将使APP mRNA不稳定，并减少APP的产生。因此，我们建议1）。为了鉴定50 sc元件的稳定功能所需的必需核苷酸，2）。确定50 sc元件是否可以单独起作用或与APP 3' UTR的其他区域协同起作用，3）。鉴定、纯化和克隆识别50 sce的RNA结合蛋白，4）。确定50 sc元件的阻断是否使转化细胞和原代神经元中的APP mRNA不稳定，5）。产生缺乏功能性50 sc元件的基因敲入小鼠。总之，这些研究将有助于揭示APP mRNA的稳定性是如何在细胞和动物模型中调节的。这些知识可能有助于抗AP的发展。

DESCRIPTION (provided by applicant):There is growing consensus that deposition of insoluble deposits of betaA4 peptide cleaved from the amyloid precursor protein (APP) are central to the pathobiology of AD. Overproduction of APP and betaA4 can result from excess APP mRNA as in patients with Down's Syndrome (DS), APP homozygous transgenic animals and a subset of late onset AD patients. We have shown that APP mRNA abundance and downstream APP synthesis are controlled post-transcriptionally by at least two, 3' untranslated region regulatory elements. The 29 base element (29be) is 200 bases 3' from the stop codon and destabilizes APP mRNA. Recently, we discovered that APP mRNA contains a hitherto unknown stabilizing element located adjacent to and extending 50 bases 3' from the stop codon (50sc element or 50sce). This region is present uniquely in APP mRNAs. At least one cytoplasmic protein interacts specifically with the 50sce. Binding activity was detected in multiple cell lines and primary cells, suggesting widespread distribution. Deletion of the 50sc element accelerated APP mRNA degradation by up to 8 fold in transfected cells and reduced APP production by approximately the same amount. Endogenous, wild type APP mRNA and protein were dramatically reduced in SH-SY-5Y cells transfected with 50sce antisense oligonucleotides or decoy mRNAs containing a single copy of the sense 50sce. Thus we hypothesize that the 50sce also regulates the rate of APP mRNA decay and does so by specific interactions with cytoplasmic binding proteins. We also hypothesize that interference with the 50sc element will destabilize APP mRNA and reduce APP production. Therefore, we propose 1). To identify the essential nucleotides required for the stabilizing function of the 50sc element, 2). Determine if the 50sc element can function alone or does so in concert with other regions of the APP 3' UTR, 3). Identify, purify and clone the RNA binding proteins which recognize the 50sce, 4). Determine if blockade of the 50sc element destabilizes APP mRNA in transformed cells and primary neurons, 5). Produce a knock-in mouse lacking a functional 50sc element. In aggregate, these studies will help unravel how APP mRNA stability is regulated in cells and animal models. This knowledge may facilitate the development of anti-AP .