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 在动作电位沿着轴突传播中的作用已经很好地 研究了 髓磷脂是神经胶质细胞质膜的延伸， 然而，它在生物化学上是非常不同的。 这种差异的一部分可能是 归因于蛋白质的组成，其特异性针对 髓鞘膜 这些蛋白质中的一种，髓磷脂蛋白脂质蛋白 (PLP)与其选择性剪接异构体DM-20一起， 约占成人CNS髓鞘中发现的总蛋白质的50%。 的比率 DM-20在发育过程中有两种亚型的变化， 然而，早在髓鞘形成之前，随着发育的进行，PLP就变成了 主要同种型。 PLP基因突变导致X连锁髓鞘形成障碍， 在人类中与Pelizaeus-Merzbacher病（PMD）有关， 痉挛性截瘫（SPG-2）。 有些PMD患者 PLP基因表达的扰动;无表达的病例（缺失 基因）或过表达。 因此，准确表达 的PLP基因是至关重要的，阐明其调控将是 有助于破译在某些细胞中发生突变的关键调控元件， PMD/SPG-2患者。 此外，重要的是要了解基因是如何 是受调节的，以帮助促进髓鞘再生过程中的人， 脱髓鞘疾病 多发性硬化最常见的脱髓鞘 疾病，一般发生在成年后，基本上髓鞘形成 期 由于PLP基因调控受发育控制， 该基因的表达在人类两岁后减少， 基本的PLP基因的调控被理解。 初步 本申请中呈现的结果表明PLP基因表达 在少突胶质细胞中，通过沉默和反沉默的相互作用来调节 通过位于第一内含子内的元件介导的机制。 一 这些元件的功能似乎是与抗沉默剂结合后， 其同源DNA结合蛋白，并且它们一起克服阻遏 由位于PLP内含子1其他位置的负调控元件介导。 本提案的总体目标是确定抗消音器， 通过PLP-lacZ缺失转染分析的负调控元件 融合基因，并表征DNA结合蛋白， 通过生物化学方法在少突胶质细胞中抗沉默。 这些研究 将增加我们对反沉默作为一种新的基因调控手段的认识， 这种调控仅在少数其他基因中被描述过。

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.