Regulation of Growth Factors and Embryogenesis

生长因子和胚胎发生的调节

• 批准号: 7903595
• 负责人: A. ANGIE RIZZINO
• 金额: $ 11.14万
• 依托单位: UNIVERSITY OF NEBRASKA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-14 至 2010-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7903595
• 关键词: Binding Sites; Cancer Biology; Cells; DNA Binding; Development; Developmental Biology; Embryonic Development; Enhancers; Ensure; Exhibits; Feedback; Gene Targeting; Genes; Genetic Transcription; Goals; Growth Factor; Molecular; Play; Regenerative Medicine; Regulation; Regulator Genes; Role; Stem cells; Testing; Work; base; embryonic stem cell; insight; novel; overexpression; proto-oncogene protein kfgf; self-renewal; transcription factor

DESCRIPTION (provided by applicant): The goal of this study is to broaden our understanding of a gene regulatory network that plays key roles during embryogenesis. Recent studies argue strongly that the transcription factors Sox2 and Oct-3/4 each exhibit important hallmarks of master regulators that orchestrate mammalian embryogenesis and the self-renewal of embryonic stem (ES) cells. Sox2 and Oct-3/4 have been shown to work together cooperatively to coordinate the transcription of at least 6 genes (FGF-4, UTF1, Fbx15, Nanog, Sox2 and Oct-3/4) expressed during embryogenesis and by ES cells. These genes are referred to as Sox2:Oct-3/4 target genes. The work proposed here is based on 3 novel findings and hypotheses. First, we recently identified 19 additional genes that are likely to be part of the Sox2:Oct-3/4 gene regulatory network. Given that 4, and possibly 5, of the 6 known Sox2:Oct-3/4 target genes are essential for embryogenesis it is our central hypothesis that the majority of Sox2:Oct-3/4 target genes play critical roles during embryogenesis, and that many are required for the self-renewal of ES cells. Second, the expression of the 6 known Sox2:Oct-3/4 target genes was shown to be very heavily dependent on closely spaced DNA binding sites for Sox2 and Oct-3/4 in the enhancer of each gene. These and other studies led us to hypothesize that the Sox2:Oct-3/4 gene regulatory network is controlled coordinately by a shared set of co-activators, at least some of which are themselves regulated during differentiation and, thus, are key players in cell fate determination. Third, although Sox2, in combination with Oct-3/4, is known to stimulate the expression of Sox2:Oct-3/4 target genes in stem cells, we determined that at least 5 of the 6 Sox2:Oct-3/4 target genes, including the Sox2 gene itself, are inhibited when Sox2 is overexpressed. These findings led to our hypothesis that Sox2:Oct-3/4 target genes are regulated carefully by a negative, as well as a positive, feedback loop to ensure that these genes are expressed at levels required for embryogenesis. Three Specific Aims are proposed to test these hypotheses. 1) Examine a newly identified set of putative Sox2:Oct-3/4 target genes for their effects on the self-renewal of ES cells and mammalian development. 2) Examine the roles of specific co-activators in the expression of Sox2:Oct-3/4 target genes. 3) Determine the molecular mechanisms by which Sox2 overexpression inhibits the expression of Sox2:Oct-3/4 target genes. Together, these studies will provide a mechanistic understanding of a critical gene regulatory network that orchestrates embryogenesis and controls the self-renewal of ES cells. As such, these studies will provide novel insights and have significant impact on developmental biology, regenerative medicine and cancer biology.

描述(申请人提供)：这项研究的目标是扩大我们对在胚胎发育过程中起关键作用的基因调控网络的理解。最近的研究有力地表明，转录因子Sox2和Oct-3/4都是调控哺乳动物胚胎发生和胚胎干细胞自我更新的重要调控因子。Sox2和Oct-3/4被证明协同工作，以协调至少6个基因(成纤维细胞生长因子-4、UTF1、Fbx15、Nanog、Sox2和Oct-3/4)在胚胎发育和ES细胞中的转录。这些基因被称为Sox2：Oct-3/4靶基因。这里提出的工作是基于3个新的发现和假设。首先，我们最近确定了另外19个基因，这些基因可能是Sox2：Oct-3/4基因调控网络的一部分。鉴于已知的6个Sox2：Oct-3/4靶基因中有4个(可能是5个)是胚胎发生所必需的，我们的中心假设是大多数Sox2：Oct-3/4靶基因在胚胎发育过程中发挥关键作用，其中许多基因是ES细胞自我更新所必需的。其次，已知的6个Sox2：Oct-3/4靶基因的表达严重依赖于每个基因增强子中紧密分布的Sox2和Oct-3/4的DNA结合位点。这些和其他研究使我们假设Sox2：Oct-3/4基因调控网络由一组共同的共激活因子协调控制，其中至少有一些在分化过程中自身受到调节，因此是决定细胞命运的关键角色。第三，虽然已知Sox2与Oct-3/4联合使用可以刺激干细胞中Sox2：Oct-3/4靶基因的表达，但我们确定当Sox2过表达时，至少有5个Sox2：Oct-3/4靶基因被抑制，包括Sox2基因本身。这些发现导致了我们的假设，即Sox2：Oct-3/4靶基因受到负反馈环和正反馈环的仔细调控，以确保这些基因在胚胎发育所需的水平上表达。为了检验这些假说，本文提出了三个具体目标。1)研究一组新发现的可能的Sox2：Oct-3/4靶基因对ES细胞自我更新和哺乳动物发育的影响。2)检测特异性共激活子在Sox2：Oct-3/4靶基因表达中的作用。3)确定Sox2过表达抑制Sox2：Oct-3/4靶基因表达的分子机制。总之，这些研究将为协调胚胎发生和控制ES细胞自我更新的关键基因调控网络提供一个机械性的理解。因此，这些研究将提供新的见解，并对发育生物学、再生医学和癌症生物学产生重大影响。