Pathogenesis of wpk-induced Renal and Cerebral Disease

描述(申请人提供)：遗传性肾囊性疾病，包括各种形式的多囊肾病(PKD)是常见的疾病，通常累及多个器官。有许多人类基因，当突变时，会导致不同的囊性表型和不同的肾外表现。有几种啮齿动物模型，其中一些带有已知的人类PKD基因突变。其他模型代表了啮齿动物的PKD基因，但也可以作为其他啮齿动物模型和人类PKD的修饰基因。然而，所有这些模型都为我们对PKD的认识做出了重要贡献。目前的提议将分离引起类似于人类常染色体隐性遗传性PKD的肾脏变化的大鼠WPK基因。此外，受影响的大鼠具有类似于人类口面部-指骨、生殖盖骨和脑-肾-指骨综合征的脑缺陷(脑积水伴胼胝体发育不全或发育不良)。目前，我们将WPK基因定位于大鼠5号染色体的2Mb区域，该区域含有啮齿动物PKD修饰基因和大约20个基因。我们研究的长期目标是确定与肾囊变有关的基因和途径，以便开发治疗干预措施。我们假设WPK基因代表一个人的PKD基因和/或一个修饰基因。1)将Wistar-WPK大鼠与近交系棕色挪威大鼠杂交，利用染色体标记对WPK基因进行定位，从而鉴定、克隆和鉴定WPK基因。除了定位方法外，我们还将从2Mb区域识别候选基因，并使用RT-PCR和从该区域筛选大鼠EST来进行测试。一旦确定，将使用器官表达和免疫组织化学来鉴定表达该基因产物的组织和细胞。WPK基因及其蛋白产物的鉴定将使人们能够深入了解囊变发生，以及关于肾脏和大脑发育的共同途径的重要信息。这个模型和WPK基因之所以重要，主要有两个原因：a)它们有囊性疾病和类似于一些人类情况的独特的脑病理；b)WPK位于已知改变其他啮齿动物形式的PKD的染色体区域，可能是PKD(啮齿动物和人类)的重要修饰基因。

DESCRIPTION (provided by applicant): Inherited renal cystic diseases, including the various forms of polycystic kidney disease (PKD) are prevalent conditions that usually affects multiple organs. There are numerous human genes, which when mutated, lead to a variety of cystic phenotypes with variable extrarenal manifestations. There are several rodent models, some with mutations in known human PKD genes. Others models represent rodent PKD genes, but could also function as modifier genes for other rodent models and human PKD. However, all of these models have made important contributions to our knowledge of PKD. The present proposal will isolate the rat wpk gene which causes renal changes similar to human autosomal recessive PKD. Additionally, affected rats have a cerebral defect (hydrocephalus with agenesis or hypoplasia of the corpus callosum) similar to that seen in human oro-facial-digital, genitopatellar and cerebro-renal-digital syndromes. Currently we localized the wpk gene to a 2Mb region of rat Chromosome 5, a location known to harbor a rodent PKD modifier locus and about 20 genes. The long term goal of our research is to identify genes and pathways involved in renal cystogenesis in order to develop therapeutic interventions. We hypothesize that the Wpk gene represents a human PKD gene and/or a modifier locus. Our Specific Aim is to: 1) Identify, clone and characterize the Wpk gene by crossing the Wistar-wpk rat with inbred Brown Norway rats and using chromosomal markers to localize the gene. Aside from the positional approach, we will identify candidate genes from with the 2Mb regions to test using RT-PCR as well as by screening rat ESTs from that region. Once identified, 9organ expression and immunohistochemistry will be used to identify the tissues and cells that express this gene product. The identification of the Wpk gene and its protein product will allow insight into cystogenesis as well as important information on shared pathways in kidney and brain development. This model and the Wpk gene are important for 2 major reasons, a) they have cystic disease and unique cerebral pathology similar to a few human conditions and b) the Wpk lies in a chromosomal region known to modify other rodent forms of PKD and may be an important modifier locus for PKD (rodent and human).