先天性肾脏及尿路畸形（CAKUT）是儿童慢性肾脏病（CKD）主要原因，在产前检查提示畸形的胎儿中约占30%。GEN1是编码Holliday连接体解离的核酸酶，在小鼠模型上运用PB转座子插入技术诱导GEN1突变，可表现多种肾脏及尿路畸形；后对临床CAKUT患者的GEN1基因进行检测，发现三个错义突变及一个无义突变。以上提示GEN1可能为CAKUT的候选基因。本课题拟用GEN1突变小鼠模型为研究对象，观察其CAKUT临床表型与预后的关系；并利用Hoxb7/myr-Venus转基因荧光蛋白工具小鼠，明确GEN1在小鼠泌尿系统发育过程中定位及表达水平变化，通过体内实验及体外胚肾培养探讨GEN1突变对小鼠后肾发育过程中UB分支的影响，探讨其调控后肾发育信号通路，进而阐明GEN1参与CAKUT发生的分子机制，为临床开展相关疾病的早期分子诊断提供依据。

Congenital anomalies of the kidney and urinary tract anatomy (CAKUT) are the primary cause of chronic kidney disease(CKD) in childhood. CAKUT represents approximately 30% of all the prenatally diagnosed malformations. GEN1 encodes a Holliday junction resolvase which was discovered recently. GEN1 PB/PB and GEN1 PB/+ mice made by PB transposon shows varied phenotype of CAKUT and abnormality of growth of uritary bud(UB),which may due to the action on GNDF signal caused by the mutation of GEN1.A nonsense mutation and three missense mutations were detected in patients with CAKUT.All the above indicates that GEN1 may play a role in causing CAKUT. The Hoxb7/myr-Venus mice are a new transgenic line, in which the outlines of Wolffian duct and ureteric bud epithelial cells are strongly labeled by fluorescent protein at all stages of urogenital development, allowing the shapes and arrangements of individual cells in freshly excised and cultured kidneys both could be readily observed by confocal microscopy. This strain is extremely useful for studies of cell behavior during ureteric bud branching morphogenesis in wild type and mutant mouse. Using this strain,we plan to observe the expression level and location of GEN1 during the development of kidney and urinary tract of mice; to identify the effect of GEN1 mutation on the UB branching morphogenesis,and explore the underlying pathway that GEN1 may regulate the development of metanephros of mice. So as to clarify the molecular mechanisms that GEN1 involved in the occuring of CAKUT and provide a theoretical basis for the early clinical molecular diagnosis of related diseases.