Role of ESE-2 Ets factor in Epithelial biology

描述(由申请人提供)： 细胞增殖和分化之间的平衡对上皮的生理功能至关重要，因此在一定程度上受到转录因子的调节，转录因子在这些过程中控制基因的表达。先前的工作表明，ESE转录因子家族可能在上皮发育和功能特化中发挥重要作用。我们利用皮肤角质形成细胞作为模型系统来研究ESE-2的生物学作用。我们对ESE-2启动子的初步研究导致了一种新的核因子KSF的鉴定，在所有测试的细胞类型中，KSF仅限于角质形成细胞，并且对启动子的活性很重要。为了深入了解ESE-2的生物学功能，我们已经开始了对该蛋白质的结构-功能分析。我们发现重组的ESE-2亚型可以与已知的Ets结合位点结合。然而，ESE-2的最佳DNA靶点包括核心基序和侧翼序列仍有待确定。为了明确ESE-2在体内的作用并确定其靶基因，我们成功地在胚胎干细胞克隆中靶向了ESE-2基因。我们的研究表明，深入分析ESE-2的作用机制、生物学作用以及确定调节其表达的因素将有助于更好地理解上皮细胞的分化过程。 因此，在目前的提案中，我们试图确定和表征控制ESE-2上皮特异性表达的调控因子，包括KSF蛋白(目标1)，对所有ESE-2亚型进行全面的结构-功能分析，以确定它们的共同结合部位，并表征对其在皮肤表皮中的特定作用至关重要的潜在激活或抑制结构域(目标2)，并采用体内敲除模型系统来评估ESE-2在上皮发育和分化过程中的生物学作用，并确定ESE-2靶标(目标3)。我们的研究将为研究ESE-2控制和塑造上皮生长和分化的分子机制以及识别这些过程的重要调控因素提供工具。因此，建议的研究将提供对正常生理状态和异常病理状态下的上皮细胞生物学的基本见解。这些知识对于开发新的治疗方法和治疗包括癌症在内的一系列困扰上皮细胞的疾病至关重要。

DESCRIPTION (provided by applicant): The balance between cell proliferation and differentiation is critical to the physiological function of the epithelium and is therefore well regulated, in part by transcription factors that control gene expression during these processes. Previous work has suggested that the ESE family of Ets transcription factors may play an important role in epithelial development and functional specialization. We have utilized skin keratinocytes as a model system to examine the biological role of ESE-2. Our preliminary studies characterizing the ESE-2 promoter have led to identification of a novel nuclear factor, KSF, that among all the cell types tested is restricted to keratinocytes and is important for the promoter activity. In order to gain insights into the biological function of ESE-2, we have begun a structure-function analysis of the protein. We show that recombinant ESE-2 isoforms can bind to known Ets-binding sites. However, the optimum DNA target for ESE-2 including the core motif and the flanking sequences remains to be determined. In order to define the in vivo role of ESE-2 and identify its target genes we have successfully targeted the ESE-2 gene in embryonic stem cell (ES) clones. Our studies indicate that a thorough analysis of the mechanism of action of ESE-2, its biological role and the identification of factors that regulate its expression should lead to a better understanding of epithelial cell differentiation process. Therefore, in the present proposal we seek to identify and characterize the regulatory factors that control the epithelium-specific expression of ESE-2, including the KSF protein (Aim 1), to perform a comprehensive structure-function analysis of all ESE-2 isoforms to identify their consensus binding sites and to characterize potential activation or repression domains that are critical for their specific roles in skin epidermis (Aim 2), and to employ an in vivo knock out model system to assess the biological role of ESE-2 during epithelial development and differentiation and to identify ESE-2 targets (Aim 3). Our studies will provide the tools to investigate the molecular mechanisms by which ESE-2 controls and shapes epithelial growth and differentiation and to identify important modulators of these processes. The studies proposed will thus provide fundamental insights into the biology of epithelial cells during both normal physiological conditions and abnormal pathological states. Such knowledge is vital to developing new therapies and cures for a wide array of diseases that afflict the epithelial cells including cancers.