ANTISILENCING OF PLP GENE EXPRESSION IN OLIGODENDROCYTES

描述：髓鞘是由中枢神经系统中的少突胶质细胞产生的，其 动作电位在沿着轴突传播中的作用一直很好 学习。髓鞘是神经胶质细胞质膜的延伸， 然而，它在生化上是非常不同的。这种差异的一部分可能是 归因于特定靶向于 髓鞘膜。其中一种是髓鞘蛋白脂蛋白 (PLP)及其选择性剪接异构体DM-20解释了 成人中枢神经系统髓鞘中的蛋白质约占总蛋白质的50%。这一比例是 发育过程中DM-20表达的两种异构体变化 然而，早在髓鞘形成之前，随着发育的进行，PLP就成为 主要异构体。PLP基因突变导致X连锁髓鞘障碍和 与Pelizaeus-Merzbacher病(PMD)和 某些类型的痉挛截瘫(SPG-2)。一些患有PMD的人显示 PLP基因表达紊乱；无表达的情况(缺失 该基因)或过表达已被描述。因此，准确的表达 PLP基因的表达是至关重要的，对其调节的阐明将是 有助于破译在某些情况下发生突变的关键监管要素 PMD/SPG-2患者。此外，重要的是要了解基因如何 是受调控的，以帮助促进慢性粒细胞白血病患者的重新髓鞘形成过程 脱髓鞘疾病。多发性硬化是最常见的脱髓鞘 疾病，一般发生在成人的髓鞘形成之后。 句号。由于PLP基因调控是发育控制的， 在人类中，这种基因的表达在两岁后会减少 了解PLP基因调控的基本原理。初步 本申请的结果表明，plp基因表达 在少突胶质细胞中受沉默和反沉默的相互作用调节 通过位于第一内含子内的元件调节的机制。一 这些元素中的一种似乎在与这些元素结合时起到抗静音剂的作用 它的同源DNA结合蛋白和它们一起压倒了抑制 由PLP内含子1其他地方的负调控元件介导。 这项提案的总体目标是确定抗消音剂和 PLP-LacZ缺失转染法分析负性调控元件 融合基因并鉴定促进基因表达的DNA结合蛋白 生化方法在少突胶质细胞中的抗沉默作用。这些研究 将增加我们对抗沉默作为一种新的基因手段的认识 仅对其他几个基因描述的调控。

DESCRIPTION: Myelin is produced by oligodendrocytes in the CNS, and its role in propagation of the action potential along the axon has been well studied. Myelin is an extension of the glial cell's plasma membrane, however, it is biochemically very different. Part of this difference can be attributed to the composition of proteins specifically targeted to the myelin membrane. One of these proteins, the myelin proteolipid protein (PLP) together with its alternatively spliced isoform DM-20 accounts for about 50% of the total protein found in adult CNS myelin. The ratio of the two isoforms changes during development with expression of DM-20 occurring well before myelination, however, as development proceeds, PLP becomes the major isoform. Mutation in the PLP gene cause X linked dysmyelination and in humans has been associated with Pelizaeus-Merzbacher disease (PMD) and some types of spastic paraplegia (SPG-2). Some people with PMD show perturbations in PLP gene expression; cases of no expression (deletion of the gene) or overexpression have been described. Thus, accurate expression of the PLP gene is critical and elucidation of its regulation will be helpful in deciphering critical regulatory elements that are mutated in some PMD/SPG-2 patients. Furthermore, it is important to understand how the gene is regulated, to help promote the remyelination process in people with demyelinating diseases. Multiple Sclerosis the most common demyelinating disease, generally occurs in adult substantially after the myelination period. Since PLP gene regulation is developmentally controlled and expression of the gene decreases after the age of two in humans, it is fundamental the regulation of the PLP gene be understood. Preliminary results presented in this application suggest that the PLP gene expression in oligodendrocytes is regulated by interplay of silencing and antisilencing mechanisms mediated through elements located within the first intron. One of these elements appears to function as and antisilencer upon binding with its cognate DNA-binding protein and together they override repression mediated by negative regulatory elements located elsewhere in PLP intron 1. The overall objectives of this proposal are to identify the antisilencer and negative regulatory elements by deletion transfection analysis with PLP-lacZ fusion genes and to characterize the DNA binding protein which promotes antisilencing in oligodendrocytes by biochemical approaches. These studies will increase our knowledge of antisilencing as a novel means of gene regulation which has been described for only a few other genes.