Regulation of Vascular Endothelial Gene Expression

描述（由申请人提供）：本项目的总体目标是增加对血管内皮基因表达的转录调控的理解，特别是在胚胎血管系统发育期间。Ets家族转录因子与血管内皮基因表达的调控密切相关，Ets因子的结合位点存在于大多数血管基因的调控区域。最近，Kruppel样因子（Klf）家族转录因子的几个成员也被证明可以调节血管基因的表达。然而，到目前为止，在小鼠模型中敲除Klf基因未能证明血管发育对Klf序列的任何需要。我们对VEGF受体基因Flk-1转录调控的研究表明，Klf结合位点对Flk-1基因的发育表达至关重要。此外，我们已经表明Klf 2在青蛙胚胎中的表达足以激活血管标记物的异位表达。我们发现Klf 2蛋白与Ets家族的血管特异性成员Erg物理相关，并且Klf 2和Erg协同作用以激活血管标记物的表达。我们的中心假设是，Ets和Klf蛋白合作，以调节大量的必需血管基因的表达。Ets和Klf家族蛋白的合作是一个新的观察，具有重要意义的血管发育和血管发病机制中的基因调控。具体目标是：目标1。确定胚胎血管发育期间和成熟内皮细胞中内皮基因表达对Klf因子的需求。目标二。确定有效转录激活所需的Ets和Klf DNA结合位点的间距和方向。目标3。鉴定Ets/Klf协同调控的潜在直接靶点内皮细胞基因。公共卫生相关性：这项研究将研究两个家族的转录因子（Ets和Kruppel样因子- Klfs）在早期胚胎发育过程中调节内皮基因表达的合作。这些研究的结果将增加对人类血管发育先天性缺陷的原因的理解，并提高我们对血管病理学相关基因表达的理解。

DESCRIPTION (provided by applicant): The overall goal of this project is to increase understanding of the transcriptional regulation of vascular endothelial gene expression, especially during development of the embryonic vascular system. Ets family transcription factors have been strongly implicated in regulation of vascular endothelial gene expression and binding sites for Ets factors are present in the regulatory regions of most vascular genes. More recently several members of the kruppel-like factor (Klf) family of transcription factors have also been demonstrated to regulate expression of vascular genes. So far however, knockout of Klf genes in the mouse model has failed to demonstrate any requirement of Klf sequences for vascular development. Our studies of transcriptional regulation of the VEGF receptor gene, Flk-1, have revealed that a Klf binding site is essential for developmental expression of the Flk-1 gene. Furthermore, we have shown that expression of Klf2 in the frog embryo is sufficient to activate ectopic expression of vascular markers. We find that Klf2 protein physically associates with Erg, a vascular specific member of the Ets family and that Klf2 and Erg function synergistically to activate expression of vascular markers. Our central hypothesis is that Ets and Klf proteins cooperate to regulate expression of a large number of essential vascular genes. Cooperation of Ets and Klf family proteins is a novel observation that has important implications for vascular development and for gene regulation in vascular pathogenesis. The specific aims are: Aim 1. To determine the requirement for Klf factors for endothelial gene expression during embryonic vascular development and in mature endothelial cells. Aim 2. To determine the spacing and orientation of Ets and Klf DNA binding sites required for efficient transcriptional activation. Aim 3. To identify endothelial genes that are potential direct targets of Ets/Klf cooperative regulation. PUBLIC HEALTH RELEVANCE: Research in this proposal will study cooperation between two families of transcription factors (Ets and Kruppel-like factors - Klfs) in regulation of endothelial gene expression during early embryonic development. Results of these studies will increase understanding of the causes of congenital defects of human vascular development and improve our understanding of gene expression related to vascular pathology.