Characterization of alpha-actinin-4 deficient mice

描述（由申请人提供）： 我们已经开发了一种缺乏Actn 4的小鼠模型，Actn 4是人类局灶节段性肾小球硬化症基因ACTN 4的小鼠同源物。这些Actn 4-/-小鼠发生蛋白尿、异常肾小球足细胞形态和进行性肾衰竭。白细胞趋化性，细胞骨架功能的敏感指标，在这些突变小鼠中改变。我们建议使用这个模型来更好地理解Actn 4-/-的作用，特别关注细胞-基质相互作用和细胞运动。 我们将： 1.对Actn 4-/-和Actn 4小鼠表型进行详细表征。我们将定义这种突变的表型效应的自然史。我们将在纯背景下繁殖小鼠，以最大限度地减少表型中的Actn 4独立变异性。我们将在组织学、生物化学和蛋白质表达水平上表征这些小鼠的肾脏。我们将表征突变胚胎和新生儿，以确定我们在Actn 4-/-小鼠中观察到的围产期死亡率增加的原因。 2.检查α-辅肌动蛋白-4缺乏对细胞粘附和运动的影响。我们将评估整合素介导白细胞运动改变的作用。我们将研究PI 3激酶信号在介导这种行为中的作用。我们将这些实验扩展到其他细胞类型，特别是成纤维细胞和足细胞。我们还将研究α-辅肌动蛋白-4缺乏对这些细胞的细胞骨架和生长特性的影响。3.开发“floxed”Actn 4等位基因以产生足细胞特异性Actn 4敲除小鼠。该模型将使我们能够剖析足细胞特异性对Actn 4-/-表型的贡献，并促进Actn 4在其他细胞类型中的作用的研究。

DESCRIPTION (provided by applicant): We have developed a mouse model deficient in Actn4, the murine homolog of the human focal segmental glomerulosclerosis gene ACTN4. These Actn4-/- mice develop proteinuria, abnormal glomerular podocyte morphology, and progressive kidney failure. Leukocyte chemotaxis, a sensitive indicator of cytoskeletal function, is altered in these mutant mice. We propose to use this model to better understand the role of Actn4-/-, with a particular focus on cell-matrix interactions and cell motility. We will: 1. Perform detailed characterization of the Actn4-/- and Actn4 mouse phenotypes. We will define the natural history of the phenotypic effect of this mutation. We will breed mice onto pure backgrounds to minimize Actn4-independent variability in the phenotype. We will characterize kidneys from these mice at histologic, biochemical, and protein expression levels. We will characterize mutant embryos and neonates in order to define the cause of increased perinatal mortality we observe in Actn4-/- mice. 2. Examine the effects of alpha-actinin-4 deficiency on cell adhesion and movement. We will assess the role of integrins in mediating altered leukocyte motility. We will examine the role of PI 3- kinase signaling in mediating this behavior. We will extend these experiments to other cell types, specifically, fibroblasts and podocytes. We will also examine the effect of alpha-actinin-4 deficiency cytoskeletal and growth properties of these cells. 3. Develop a "floxed" Actn4 allele in order to create a podocyte-specific Actn4 knockout mouse. This model will allow us to dissect the podocyte-specific contribution to the Actn4-/- phenotype and facilitate studies of the role of Actn4 in other cell types.