EWS/FLI Regulates Transcriptional Activation in Ewing Sarcoma via Length Dependent GGAA Microsatellites

项目摘要/摘要 我们在这个项目中的长期目标是阐明尤因肉瘤的分子和细胞生物学 发展并将这一知识转化为儿科癌症的进展。尤因肉瘤，第二例 最常见的儿童恶性骨肿瘤，以染色体易位t(11；22)为特征。这个 融合癌蛋白EWS/FLI是致癌所必需的异常转录因子 尤因细胞的转化。EWS作为一个氨基末端转录激活域与 其ETS家族成员犯罪伙伴FLI的羧基末端DNA结合域。微卫星重复序列 以GGAA基序为特征，作为EWS/Fli在上调靶标启动子内的结合位点 尤因肉瘤中的基因。以前被认为是“垃圾DNA”，这些多态的微卫星作为 EWS/FLI DNA结合的反应元件与有趣的遗传相关性和可能的临床 这意味着什么。虽然EWS/FLI直接和间接地激活和抑制了许多靶基因，但如何 EWS/FLI区分是否上调或下调基因表达仍未确定。因此， 本文提出的实验旨在验证EWS/FLI诱导癌基因转化和 通过长度决定结合和效应子的GGAA微卫星调节转录激活 功能。因此，我们的目标是：1)确定GGAA微卫星在多大程度上发挥增强反应的作用 2)确定GGAA基序长度在尤文肉瘤转录激活中的作用。这 项目是儿童癌症的一个重要方法，因为它提供了一个理解致癌因素的模型 生物标志物和治疗开发所需的转录调控，以改善患者护理和治疗 总体存活率。

Project Summary/Abstract Our long-term goal in this project is to elucidate the molecular and cellular biology for Ewing Sarcoma development and translate this knowledge into advances for pediatric cancer. Ewing sarcoma, the second most common pediatric malignant bone tumor, is characterized by a chromosomal translocation t(11;22). The resulting fusion oncoprotein EWS/FLI is an aberrant transcription factor necessary for oncogenic transformation in Ewing cells. EWS acts as an amino-terminal transcriptional activation domain linked to the carboxy-terminal DNA-binding domain of its ETS family member partner in crime, FLI. Microsatellite repeats characterized by the motif GGAA serve as binding sites for EWS/FLI within the promoters of upregulated target genes in Ewing Sarcoma. Previously thought of as “junk DNA,” these polymorphic microsatellites serve as response elements for EWS/FLI DNA binding with interesting genetic correlations and possible clinical implications. Though EWS/FLI both activates and represses numerous target genes directly and indirectly, how EWS/FLI distinguishes whether to up or down regulate gene expression remains undetermined. Therefore, the experiments proposed herein aim to test the hypothesis that EWS/FLI induces oncogenic transformation and regulation of transcriptional activation via GGAA microsatellites whose length dictates both binding and effector function. Thus our aims are: 1) Determine to what extent GGAA microsatellites function as enhancer response elements and 2) Determine the role of GGAA motif length in transcriptional activation in Ewing Sarcoma. This project is an important approach to pediatric cancer because it provides a model of understanding oncogenic transcriptional regulation necessary for biomarker and therapeutic development to improve patient care and overall survival.