Co-regulation and function of Pur-gamma and WRN in the CNS

项目总结/摘要 该项目将阐明两种蛋白质的功能的机制，已知这两种蛋白质对 中枢神经系统的发育和基因组不稳定性的预防，分别通过共享的基因协调， 调节和协同蛋白活性。WRN基因突变导致早衰症Werner 综合征，其特征在于基因组不稳定性和早期衰老。神经变性是一种 Werner综合征的症状我们的总体假设是，编码Pur-gamma（Purg）的PURG基因， Pur蛋白家族中很少研究的成员，在特定时间与WRN基因协调调节 并且这两种编码的蛋白质协同工作。PURG和WRN是面对面的， 由92 bp的共享控制序列隔开。这两种蛋白质执行DNA链的不同方面 分离和进行性解旋。Purg在神经胶质细胞和神经元中表达，并且其存在于 早期大脑发育中的高水平，WRN也是如此。Purg先前已显示具有两种同种型， 我们发现这两种亚型都存在于少突胶质细胞瘤细胞的细胞核和核仁中。Pur 蛋白质参与局部DNA链分离，它们与称为PUR的富含G的序列结合 元素WRN蛋白也偏好富含G的序列，并且是一种进行性解旋酶， 解旋DNA与抑制或增强其活性的辅因子。我们假设PURG和WRN基因 被共调节以允许Purg在已知WRN功能中的协调功能，包括DNA修复和 端粒稳态，在中枢神经系统的细胞。我们这个项目的基本原理是：1）WRN和Purg蛋白 WRN和Purg在神经细胞中相互作用并共定位; 2）WRN和Purg具有密切的相关性， 互补功能，两者都有利于DNA修复;和3）WRN和PURG基因启动子 共享监管要素。该项目有两个具体目标。第一个将决定如何清洗和 WRN基因在神经胶质细胞中通过共享的中央控制区中的序列元件协调调节。 第二个将确定Purg和WRN蛋白在DNA中协同作用的方式 在初级神经细胞中修复。从这些数据中获得的见解不仅对阐明 这两种蛋白质发挥作用的细胞途径，也有助于增强我们对这一过程的理解。 通常在神经退行性疾病中被破坏。

PROJECT SUMMARY/ABSTRACT This project will elucidate the mechanisms by which functions of two proteins, known to be important for CNS development and prevention of genomic instability, respectively, are coordinated through shared gene regulation and cooperative protein activity. Mutations in the WRN gene lead to the progeroid disorder Werner syndrome, which is characterized by genomic instability and early senescence. Neurodegeneration is a feature of Werner syndrome. Our overall hypothesis is that the PURG gene encoding Pur-gamma (Purg), a little studied member of the Pur protein family, is coordinantly regulated at specific times with the WRN gene and that the two encoded proteins function cooperatively. PURG and WRN are located head-to head and are separated by a shared control sequence of 92 bp. The two proteins carry out distinct aspects of DNA strand separation and processive unwinding. Purg is expressed in both glial cells and neurons, and it is present at high levels in early brain development, as is WRN. Purg has previously been shown to have two isoforms, and we have found both isoforms to be present in the nucleus and nucleolus of oligodendroglioma cells. Pur proteins are involved in local DNA strand separation, and they bind to G-rich sequences called PUR elements. The WRN protein also has a preference for G-rich sequences and is a processive helicase that unwinds DNA with cofactors that inhibit or enhance its activity. We hypothesize that PURG and WRN genes are coregulated to allow coordinate function of Purg in known WRN functions, including DNA repair and telomere homeostasis, in cells of the CNS. Our rationale for this project is that 1) WRN and Purg proteins interact and colocalize with each other in neural cells; 2) WRN and Purg have closely related and potentially complementary functions both advantageous for DNA repair; and 3) the WRN and PURG gene promoters share regulatory elements. This project has two specific aims. The first will determine how the PURG and WRN genes are coordinately regulated in glial cells via sequence elements in a shared central control region. The second will determine the manner in which the Purg and WRN proteins function cooperatively in DNA repair in primary neural cells. Insights from these data will be of significance not only for the elucidation of the cellular pathways in which these two proteins function, but also for enhancing our understanding of a process commonly disrupted in neurodegenerative diseases.