ETS FACTOR NERF AND VASCULOGENESIS

血管生成是指在发育中的胚胎中形成血管和初级血管网络。血管内皮生长因子、成纤维细胞生长因子、血管生成素及其受体Flk-1、Flt-1、Tie1和Tie2是这些事件的重要介导者。尽管我们对这些生长因子及其受体的了解越来越多，但对于在这一过程中调节血管特异性基因表达的因子却知之甚少。这个项目的长期目标是了解血管生成的转录调控。ETS基因是一个转录因子家族，调节发育过程和细胞分化。一些血管特异基因最近被证明具有进化保守的ETS因子结合位点，而ETS因子对内皮特异基因的表达至关重要。特别是，在Tie1和Tie2基因的启动子中有保守的Ets位点，这是这些基因血管定向表达所必需的。NERF是ETS家族中的一个新成员，表达于内皮细胞，调控Tie1和Tie2基因。一种与NERF高度同源的新的鸡ETS因子CAM-Ets4富含在鸡绒毛膜尿囊膜(CAM)发育中的血管中。在体外Matrigel血管生成模型中，NERF基因的异常表达导致血管管道和通道的形成受损。这些研究的假设是，ETS因子家族中选定的成员，特别是NERF，是血管发育和内皮功能的关键调节因子。其具体目的是(1)确定NERF在发育过程中的时间、空间和细胞表达模式，以及细胞分化；(2)确定NERF基因表达变化对内皮功能和血管生成的影响；(3)进一步鉴定鸡NERF同源物在鸡血管发育过程中的特征。用于实现这些特定目的的方法包括原位杂交、免疫组织化学、胚胎干细胞分化模型、DNAseI足迹、凝胶迁移分析、体外和体内血管发育模型、转基因动物和逆转录病毒基因传递。更好地了解血管发育的转录调节因子不仅将为血管生成发育缺陷的病因学提供新的线索，而且将为调控癌症或冠状动脉缺血等疾病状态下的血管发育或血管生成提供新的治疗途径。

Vasculogenesis is the formation of blood vessels and a primary vascular network in the developing embryo. Several growth factors including vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), Angiopoeitin, and their receptors Flk-1, Flt-1, Tie1, and Tie2 have been identified as being important mediators of these events. Despite our increasing knowledge of these growth factors and their receptors, much less is known about the factors which regulate vascular-specific gene expression during this process. The long term goal of this project is to understand the transcriptional regulation of vasculogenesis. The Ets genes are a family of transcription factors that regulate developmental processes and cellular differentiation. Several vascular-specific genes have recently been shown to have evolutionary conserved binding sites for Ets factors, which are critical for endothelial-specific gene expression. In particular, there are conserved Ets sites within the promoters of the Tie1 and Tie2 genes, which are necessary for vascular directed expression of these genes. NERF is a novel member of the Ets family which is expressed in endothelial cells and regulates the Tie1 and Tie2 genes. A novel chicken Ets factor, CAM-Ets4, which is highly homologous to NERF, is enriched in the developing blood vessels of the chicken chorioallantoic membrane (CAM). Aberrant NERF gene expression leads to the impaired formation of vascular tubes and channels in an in vitro matrigel model of angiogenesis. The hypothesis for these studies is that selected members of the Ets factor family and in particular NERF, are critical regulators of vascular development and endothelial function. The Specific Aims are to (1) Determine the temporal, spatial, and cellular expression pattern of NERF during development, and cellular differentiation (2) Determine the effects of altered NERF gene expression on endothelial function and vasculogenesis, and (3) further characterize the chicken NERF homologue during blood vessel development in the chicken. The methods used to achieve these specific aims include in situ hybridization, immunohistochemistry, embryonic stem cell differentiation models, DNAseI footprinting, Electrophoretic mobility shift assays, in vitro and in vivo models of blood vessel development, transgenic animals, and retroviral gene delivery. A better understanding of the transcriptional mediators of blood vessel development will not only provide new clues for the etiology of developmental defects in vasculogenesis, but also provide new therapeutic avenues for regulating blood vessel development or angiogenesis in disease states such as cancer, or coronary ischemia.