Roles of transcription factors in kidney development

在哺乳动物中，肾脏的发育涉及后肾间充质(MM)的规范， 输尿管芽(UB)的生长及其正确的分枝形态发生 产生输尿管和肾脏收集系统。已知GDNF/Ret信号转导途径在 在小鼠的这些过程中发挥核心作用。然而，控制MM和MM规格的基因 UB及其分支形态发生的模式和GDNF表达的调控机制 在MM中，人们仍然知之甚少。这项建议的长期目标是澄清 Eya1和SIX1控制正常肾脏发育的机制。在这些基因中存在缺陷 人类导致Branchio-Oto-Renal(Bor)综合征，这是一种先天性出生缺陷，其特征是 合并颧骨、耳廓和肾脏畸形。了解发育和分子生物学 在Bor综合征中发生肾功能障碍的基础上，我们分析了在EYA1中发现的突变 和来自BOR患者的SIX1基因，并通过 基因打靶。我们的结果表明，Eya1是MM的特异体，是GDNF的关键调节因子 我们发现Eya1在SIX1的上游起作用，但两种基因产物相互作用 在肾脏发育过程中。此外，我们已经证明了SIX1是一个关键的调节因子 通过介导GDNF、SIX2和Pax2在MM中的表达来实现分支形态发生 证明在BOR患者的EYA1或SIX1基因中发现的突变 影响Eya1-SIX1相互作用或SIX1-DNA结合，从而提供了对 人类肾脏发育疾病的分子基础。此应用程序将继续定义 Eya1和SIX1基因驱动正常肾脏的分子和发育机制 发展。首先，我们将研究Eya1指定MM和驱动器的机制 正常的肾脏生成。接下来，我们将研究Eya1活性在肾脏发育中的调节。 最后，我们将确定SIX1启动分枝形态发生的机制。这些研究 应该通过以下方式显著提高我们对多层控制机制的理解 EYA1-SIX1，调节正常肾脏的发育。此外，这些结果将提供 肾功能不全的发育性和分子发病机制研究 博尔综合征。

In mammals, kidney development involves the specification of the metanephric mesenchyme (MM), the outgrowth of the ureteric bud (UB), and its correctly patterned branching morphogenesis to generate the ureter and the renal collecting system. It is known that GDNF/Ret signaling plays a central role in these processes in mice. However, the genes that control the specification of MM and pattern the UB and its branching morphogenesis, and the regulatory mechanism of Gdnf expression in the MM are still poorly understood. The long-term objective of this proposal is to elucidate the mechanisms by which Eya1 and Six1 control normal kidney development. Defects in these genes in humans cause Branchio-Oto-Renal (BOR) syndrome, a congenital birth defect characterized by combinations of branchial, otic and renal anomalies. To understand the developmental and molecular bases of renal defects that occur in BOR syndrome, we analyzed the mutations identified in the EYA1 and SIX1 genes from BOR patients functionally and generated Eya1 and Six1 mutant mice through gene targeting. Our results indicate that Eya1 specifies the MM and is a critical regulator for Gdnf expression in the MM. We found that Eya1 acts upstream of Six1 but both gene products interact during kidney development. Furthermore, we have shown that Six1 is a critical regulator for branching morphogenesis by mediating the expression of Gdnf, Six2 and Pax2 in the MM. We also demonstrated that the mutations identified in either the EYA1 or SIX1 gene from BOR patients affected either Eya1-Six1 interaction or Six1-DNA binding, thus providing new insights into the molecular basis of renal developmental diseases in humans. This application will continue to define the molecular and developmental mechanisms by which the Eya1 and Six1 drive normal kidney development. First, we will investigate the mechanisms by which Eya1 specifies the MM and drives normal nephrogenesis. Next, we will investigate the regulation of Eya1 activity in kidney development. Lastly, we will define the mechanism by which Six1 initiates branching morphogenesis. These studies should lead to significant improvements in our understanding of the multilayer control mechanisms by Eya1-Six1 that mediate development of a normal kidney. In addition, these results will provide important insights into the developmental and molecular pathogenesis of renal defects occurring in BOR syndrome.