LAMININ GENE EXPRESSION IN GLOMERULAR CELLS

肾小球硬化是进行性肾脏疾病最严重的后遗症。肾小球硬化由一种 肾小球基底膜(GBM)中蛋白质异常聚集，其中一些是正常的 和系膜基质(MM)。层粘连蛋白是肾小球内积聚的GBM和MM的组成部分之一 在肾小球疾病的进展过程中。一系列生长因子，包括转化生长因子-[_ (转化生长因子-β)，激活肾小球细胞，导致层粘连蛋白异常积聚。尽管层粘连蛋白被认为是一种 在肾小球硬化的发展中起关键作用的是，调节层粘连蛋白链表达的机制是 不完全理解。转化生长因子-[3]和其他生长因子处理肾小球细胞可提高其mRNA水平 层粘连蛋白71链。人和啮齿动物的LAMCt基因启动子含有关键的ben-1 被转录因子#E3(TFE3)激活的元件。在肾小球系膜细胞中，TFE3介导的 BCN-1元件的激活被Smad蛋白大大增强，通过LAMC1启动子的Smad-1作用。 结合元件(SBE)和转化生长因子-[3-信号通路。Bcn-L元素依赖的细胞激活作用 通过TFE3和Smad蛋白的协同作用启动LAMC1为深入了解转化生长因子-β是如何介导的 内源性LAMC1基因在这些细胞中的激活转录共激活因子CREB-1的表达 结合蛋白(CBP)，可增加系膜细胞LAMC1启动子的活性。当前的目标是 建议定义负责TFE3和Smad依赖的LAMC 1激活的分子机制 肾小球细胞中由转化生长因子-[3]诱导的基因转录。提出了以下具体目标来探索 这些机制。 我们将确定CBP和其他共激活因子在介导TFE3-Smad依赖的转化生长因子-β诱导的过程中的作用 LAMC1基因的表达。 我们将确定与TFE3蛋白相互作用的基本转录机制的组件，并定义 它们在介导转化生长因子-β1诱导的基因表达中的作用。 我们将确定TFE3-Smad3协同激活LAMC1的分子机制 基因对转化生长因子-β的反应。 这些研究将为深入了解转化生长因子-[_指导TFE3-和Smad-的转录机制提供依据。 肾小球细胞中LAMC1基因的依赖转录。这些研究的结果预计将具有广泛的 对理解转化生长因子[3]触发编码成分基因转录的基本机制的影响 细胞外基质和肾小球细胞中表达的其他基因的表达。

Glomerulosclerosis is the most serious sequela of progressive renal disease. Glomerulosclerosis results from an abnormal accumulation of proteins, some of which, that normal]y make up the glomerular basement membrane (GBM) and mesangial matrix (MM). Laminin is one of the components of GBM and MM that accumulates within glomeruti during the progression of glomerular disease. A number of growth factors including transforming growth factor-[_ (TGF-_), activate glomerular cells resulting in abnormal accumulation of laminin. Although laminin is known to play a key role in the development of glomerulosclerosis, the mechanisms that regulate expression of laminin chains are incompletely understood. Treatment of glomerular cells with TGF-[3 and other growth factors increases mRNA levels of laminin 71 chain. The human and rodent larrdnin y1 chain (LAMCt) gene promoters contain the critical ben-1 element that is activated by transcription factor #E3 (TFE3). In glomerular mesangial cells, the TFE3-mediated activation of the bcn-1 element is greatly augmented by Smad proteins, acting through the LAMC1 promoter's Smad- binding elements (SBE), and by the TGF-[3-signaling pathways. The bcn-l-element-dependent activation of the LAMC1 promoter by the synergistic action of TFE3 and Smad proteins provides insight into how TGF-_ mediates activation of the endogenous LAMC1 gene in these cells Expression of the transcriptional co-activator, CREB- binding protein (CBP), increased the activity of the LAMC1 promoter in mesangial cells. The goal of the current proposal is to define the molecular mechanisms responsible for the TFE3- and Smad-dependent activation of LAMC 1 gene transcription that is induced by TGF-[3 in glomerular cells. The following specific aims are proposed to explore these mechanisms. We will define the role of CBP and other co-activators in mediating the TFE3-Smad-dependent TGF-_-induced LAMC1 gene expression. We will identify components of the basal transcriptional machinery that interact with TFE3 protein and define their role in mediating TGF-fl-induced gene expression. We will define the molecular mechanisms responsible for the TFE3-Smad3 synergistic activation of the LAMC1 gene in response to TGF-_. These studies will provide insight into transcriptional mechanisms utilized by TGF-[_ to direct TFE3- and Smad- dependent LAMC1 gene transcription in glomerular cells. The results of these studies are anticipated to have a broad impact on understanding the basic mechanisms by which TGF-[3 triggers transcription of genes encoding components of extracellular matrix and of other genes expressed in glomerular cells.