BMP SIGNALLING IN EYE AND KIDNEY DEVELOPMENT

描述（由申请人提供）：TGF-β超家族的成员 分泌的生长因子在控制形态发生中发挥重要作用 整个开发过程。我们之前的研究表明，骨 哺乳动物眼睛的个体发育过程中需要形态发生蛋白 7 (BMP7) 和肾脏。本续订申请中概述的实验旨在阐明我们的 了解 BMP 在肾脏发育和形态发生过程中的功能。我们 将测试异源BMP替代BMP7功能的能力。至 评估输尿管中 BMP7 表达的相对贡献 上皮细胞和间充质细胞，我们将有条件地灭活这些细胞中的 BMP7 使用 Cre-lox 技术的特定细胞类型。探究其根源和 基质和间充质之间潜在的相互作用，我们将标记细胞 vivo使用二进制系统。我们计划确定负责的候选基因 通过转录谱维持未诱导的间充质。 BMP 和 TGF-β/激活素调节的 Smad 的表达域，以及 将描述抑制性Smad。我们将利用条件等位基因 Smad1选择性地从后肾间质中删除Smad1功能。至 破坏 TGF-β /BMP 信号，转基因小鼠在间充质中表达 Cre 也将与含有条件 Smad4 等位基因的动物杂交。信号 负责下调 Smad 表达 将分析间充质/上皮转化。评估候选 Wnt 信号源自新诱导的间充质或 输尿管芽，将评估 Wnt4 突变肾组织中的 Smad 表达， 以及在稳定转染的成纤维细胞上生长的分离间充质中表达 选择性 Wnt 蛋白。总的来说，这些实验应该提供见解 进入发育中肾脏的 TGF-β 信号通路。

DESCRIPTION (provided by applicant): Members of the TGF-beta superfamily of secreted growth factors play fundamental roles governing morphogenetic processes throughout development. Our previous studies have shown that Bone Morphogenetic Protein7 (BMP7) is required during ontogeny of the mammalian eye and kidney. Experiments outlined in this renewal application aim to clarify our understanding of BMP functions during kidney development and morphogenesis. We will test the ability of heterologous BMPs to replace BMP7 functions. To evaluate the relative contribution of BMP7 expression in the ureteric epithelium and mesenchyme, we will conditionally inactivate BMP7 in these specific cell types using Cre-lox technology. To investigate the origins and potential interactions between stroma and mesenchyme, we will mark cells in vivo using a binary system. We plan to identify candidate genes responsible for maintenance of the uninduced mesenchyme by transcriptional profiling. Expression domains of BMP and TGF-beta /activin regulated Smads, as well as the inhibitory Smads will be described. We will exploit a conditional allele of Smad1 to selectively delete Smad1 function from the metanephric mesenchyme. To disrupt TGF-beta /BMP signals, transgenic mice expressing Cre in the mesenchyme will also be crossed to animals harboring a conditional Smad4 allele. Signals responsible for down regulation of Smad expression during the mesenchymal/epithelial transition will be analyzed. To evaluate candidate Wnt signals originating from either the newly induced mesenchyme or from the ureteric bud, Smad expression will be assessed in Wnt4 mutant kidney tissue, and in isolated mesenchymes grown on stably transfected fibroblasts expressing selective Wnt proteins. Collectively these experiments should provide insight into TGF-beta signaling pathways in the developing kidney.