Characterization of the Murine pcy Mutation

多囊肾病（PKD）是儿童和成人进行性肾衰竭的主要原因之一。目前，还没有已知的治疗方法可以抑制或延缓PKD患者肾功能衰竭的进展。尽管最近发现了PKD1和PKD2这两个在人类PKD中最常发生突变的基因，但对PKD肾衰竭的遗传学和发病机制仍然知之甚少。纯合子pcy/pcy小鼠发展为一种缓慢进展的PKD，具有许多与人类PKD相似的特征。了解pcy小鼠的分子病变将为PKD肾衰竭发展的遗传学和致病途径提供重要的额外见解。该建议旨在阐明pcy小鼠的分子缺陷，并提高我们对决定肾囊性疾病表型严重程度的修饰基因的理解。为了在分子水平上鉴定和表征pcy突变，我们将(1)利用RPCI-23小鼠基因组文库分离BACs contigs中的最小pcy间隔，并由NIH小鼠基因组测序项目进行测序；(2)通过系统表征鉴定pcy基因；候选基因位于我们的pcy区间内。为了提高我们对调节多囊肾病表型严重程度的修饰基因的理解，我们将(1)使用标记辅助选择育种方法将两个定位的修饰位点分离到单独的同源菌株中；(2)使用基因表达谱对轻度PKD的同源小鼠肾脏和年龄匹配的重度PKD的同源小鼠肾脏中差异表达的一组基因进行分类。

Polycystic kidney diseases (PKD) are among the leading causes of progressive renal failure in children and adults. Currently, there is no known therapy that can inhibit or retard the progression to renal failure in PKD patients. Despite the recent molecular identification of PKD1 and PKD2, the two genes most commonly mutated in human PKD, the genetics and pathogenesis of renal failure in PKD remains poorly understood. Homozygous pcy/pcy mice develop a slowly progressive form PKD that has many characteristics resembling human PKD. Understanding the molecular lesion in pcy mice will provide important additional insights into the genetics and pathogenic pathways involved in the development of renal failure in PKD. This proposal aim to elucidate the molecular defect in the pcy mouse and to improve our understanding of modifier genes that determine the severity of the renal cystic disease phenotype. Towards the identification and characterization of the pcy mutation at the molecular level, we will (1) isolate the minimal pcy interval in BACs contigs using the RPCI-23 mouse genomic library for sequencing by the NIH mouse genome sequencing project and (2) identify the pcy gene by systematically characterize; candidate genes located within our pcy interval. Towards improving our understanding of modifier genes that regulates the severity of the polycystic kidney disease phenotype, we will (1) isolate the two mapped modifier loci into separate congenic strains using marker assisted selective breeding approaches and (2) use gene expression profiling to catalog the set of genes that are differentially expressed in the kidneys of congenic mice with the mild PKD and in the kidneys of age matched congenic mice with the severe PKD.