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

描述（由申请人提供）：本项目将阐明两种已知对中枢神经系统发育和预防基因组不稳定性重要的蛋白质的功能如何通过共享基因调控和合作蛋白质活性进行协调的机制。WRN基因突变可导致以基因组不稳定和早期衰老为特征的类老年性疾病Werner综合征。神经退行性变是维尔纳综合征的一个特征。我们的总体假设是，PURG基因编码Pur- γ (PURG)，这是Pur蛋白家族中研究较少的成员，在特定时间与WRN基因协调调节，并且这两种编码蛋白协同工作。PURG和WRN位于头对头的位置，由一个92 bp的共享控制序列分开。这两种蛋白质执行DNA链分离和过程解绕的不同方面。Purg在神经胶质细胞和神经元中均有表达，在早期大脑发育中，它的表达水平很高，WRN也是如此。Purg先前被证明有两种亚型，我们发现这两种亚型都存在于少突胶质细胞的细胞核和核仁中。Pur蛋白参与局部DNA链分离，它们与富含g的序列结合，称为Pur元素。WRN蛋白也偏爱富含g的序列，是一种带有抑制或增强其活性的辅助因子的解旋DNA的过程解旋酶。我们假设PURG和WRN基因是共同调控的，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，在中枢神经系统细胞中。我们这个项目的基本原理是：1)WRN和Purg蛋白在神经细胞中相互作用和共定位；2) WRN和Purg具有密切相关和潜在互补的功能，都有利于DNA修复；3) WRN和PURG基因启动子共享调控元件。这个项目有两个具体目标。第一项研究将确定PURG和WRN基因如何通过共享中央控制区的序列元件在胶质细胞中协调调节。第二项研究将确定Purg和WRN蛋白在原代神经细胞DNA修复中协同作用的方式。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具有重要意义，而且对增强我们对神经退行性疾病中通常被破坏的过程的理解也具有重要意义。

DESCRIPTION (provided by applicant): 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 coordinately 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.