先天性肾脏和尿路异常GEN1突变小鼠模型培育与研究

Congenital anomalies of the kidney and urinary tract (CAKUT) is a common birth defect and the leading cause of renal failure in children. Molecular mechanisms underlying CAKUT have not been well defined, nor do we have effective methods for the prevention and early intervention of the disease. We have found the mutation of GEN1, a recently discovered Holliday Junction resolvase, frequently leads to kidney and unrinary tract defects in mice. In addition, GEN1 mutations have been detected in CAKUT patients as well. In order to develop a new animal model model for CAKUT, we propose a detailed comparison between mouse mutants and human patients. Pathological and physiological changes of the mouse mutants will be characterized and compared to the symptoms found in patients. On the other hand, more patients will be screened for GEN1 mutations. Patient specific mutations will be evaluated for their effects on GEN1 activities. Finally, we will explore the mechanistic relation through which GEN1 could affect the development and disease of the kidney and uniary tract.

先天性肾脏和尿路异常是常见的出生缺陷，也是导致儿童肾衰竭的首要原因。该病分子机理仍不透彻，目前还不能有效预防，治疗也无特殊手段。GEN1是新发现Holliday 交叉解构酶。我们前期研究观察到GEN1突变小鼠肾脏和输尿管异常高发，并发现了携带GEN1无义突变的先天性肾脏和尿路异常患者，为培育新的疾病动物模型奠定了良好基础。本项目将一方面深入研究突变小鼠肾脏和尿路的异常改变，另一方面分析疾病患者GEN1基因序列和功能的变化，从表型和病因两方面入手评估突变小鼠与患者的相似性，评价GEN1突变体作为疾病模型的价值。项目将以动物模型为基础，研究GEN1影响肾脏发育和疾病的分子机理，为先天性肾脏和尿路异常的遗传预警和干预研究提供线索。

先天性肾脏和尿路异常（CAKUT）是常见的发育缺陷之一，具有复杂的遗传病因。我们发现DNA重组酶GEN1突变可以导致小鼠产生肾缺如、重复肾、肾和输尿管积水、尿液反流等CAKUT类似异常。我们发现GEN1突变影响GDNF和Grem1表达，并通过SIX1/EYA1转录复合物调节GDNF/Ret信号活性，导致肾脏早期发育过程中输尿管芽萌发和分支异常。我们还发现GEN1和EME1协同调控细胞对DNA损伤的敏感性和减数分裂重组，但未发现两者协同参与早期肾脏发育的明显证据。通过对342例CAKUT患者的GEN1序列分析，我们发现1例GEN1无义突变和3例GEN1错义突变。这些结果揭示了GEN1突变小鼠与CAKUT患者症状和病因的相似性，支持GEN1突变小鼠是一个新的先天性肾脏和尿路异常动物模型。