OLIGODENDROCYTE LINEAGE GENE FUNCTION IN THE CNS

在初步研究中，我们已经克隆和表征了一对少突胶质细胞谱系基因（Olg），编码一类新的bHLH蛋白。 人OLG-1和OLG-2在唐氏综合征关键区域中彼此共定位在50 kb内。 Olg基因仅在啮齿动物的中枢神经系统（CNS）内表达。 Olg的表达与已知的最早的少突胶质细胞发育标记重叠，但先于它们。 此外，在细胞培养中，病毒介导的0 lg-1的异位表达指导多能皮质祖细胞表达少突细胞谱系的早期标记。 这里描述的研究建立在这项工作的基础上。我们有四个具体的目标：目标1是确定Olg基因的表达是否足以启动动物少突胶质细胞的形成。 我们将使用双基因系统在转基因小鼠的神经管发育中实现野生型和突变型0 lg基因的条件表达。 目的2是确定Olg基因表达是否是少突胶质细胞发育所必需的。 我们将使用一种稍微不寻常的方法来产生0 lg-1和0 lg-2的经典敲除。 我们将分别通过靶向插入lacZ和Cre重组酶基因来破坏基因。 我们以这种方式创建的小鼠品系将可用于额外的实验（参见下文的具体目标3），即使在Olg敲除中不存在可辨别的表型。 目的3是确定Olg基因是否专门在少突胶质细胞的形成中起作用。 我们将通过将01 g/Cre敲除小鼠（Aim 2）与“Floxed”betageo条件报告小鼠品系交配来绘制已表达01 g基因的神经祖细胞的长期命运。 目的4是明确多能神经前体细胞中0 lg基因产物的分子功能。 我们将专注于在转录调控的作用和功能活动所需的结构特征的特点。从这些研究中获得的对Olg基因功能的见解可能会影响涉及CNS髓鞘产生细胞的广泛疾病状态。 特别是，这项工作可能揭示神经胶质肿瘤的分子表型，并指出可能的新疗法。

In preliminary studies, we have cloned and characterized a pair of Oligodendrocyte lineage genes (Olg) that encode a novel class of bHLH proteins. Human OLG-1 and OLG-2 co-localize within 50 kb of each other n the Down's Syndrome critical region. Olg genes are expressed exclusively within the central nervous system (CNS) of rodents. Olg expression overlaps, but precedes, the earliest known markers of oligodendrocyte development. Moreover, in cell culture, virus-mediated ectopic expression of 0lg-1 directs multipotent cortical progenitor cells to express early markers of the oligodendroycte lineage. The studies described here build upon this work. We have four specific aims: Aim 1 is to determine whether 0lg gene expression is sufficient to initiate the formation of oligodendrocytes in animals. We will use a bigenic system to achieve conditional expression of wild type and mutated 0lg genes in developing neural tube of transgenic mice. Aim 2 is to determine whether Olg gene expression is necessary for oligodendrocyte development. We will use a slightly unusual method to generate classical knockouts of of 0lg-1 and 0lg-2. We will disrupt the genes by targeted insertion of lacZ and Cre recombinase genes, respectively. The mouse strains that we create in this way will be useful for additional experiments (see specific aim 3 below) even if there is no discernable phenotype in the 0lg knockouts. Aim 3 is to determine whether 0lg genes function exclusively in formation of oligodendrocytes. We will map the long-term fate of neural progenitor cells that have expressed 0lg genes by mating the 0lg/Cre knockout mice (Aim 2) to a "Floxed" betageo conditional reporter mouse strain. Aim 4 is to define the molecular functions of 0lg gene products within multipotent neural progenitor cells. We will focus on roles in transcriptional regulation and characterize structural features required for functional activity. Insights into 0lg gene functions derived from these studies could impact a broad range of disease states involving myelin-producing cells of the CNS. In particular, the work may shed light on the molecular phenotype of glial tumors and point to possible new therapies.