Histone Methyltransferases and TGF-beta Signaling

组蛋白甲基转移酶和 TGF-β 信号转导

• 批准号: 6788147
• 负责人: ROBERT J LECHLEIDER
• 金额: $ 15.52万
• 依托单位: GEORGETOWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-08 至 2006-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6788147
• 关键词: biological signal transduction; bone morphogenetic proteins; cell line; gene induction /repression; genetic regulation; histones; immunoprecipitation; methyltransferase; nucleic acid sequence; protein protein interaction; reporter genes; transcription factor; transforming growth factors

DESCRIPTION (provided by applicant): This is a R21 application in response to PA 02-100 "Complex Formation in Hormonal Regulation of Gene Expression." The TGF-beta superfamily of ligands signal through receptor serine-threonine kinases that transmit their signal downstream using translocatable transcription factors called Smads. In the nucleus, Smads associate with DNA-binding proteins and transcriptional co-factors to regulate target gene expression. Loss of TGF-beta and BMP signaling have important implications for cancer, as several human cancers have been shown to have lost TGF-beta signaling capability during their development, and mutation of a receptor for BMPs has been shown in at least one hereditary cancer syndrome. It has lately become apparent that a significant component of transcriptional regulation of target genes is repression and that loss of repression is harmful to normal development and homeostasis. We have identified association of BMP regulated Smad proteins with histone methyltransferases of the Suv family. These proteins methylate histone H3 on lysine 9 and cause transcriptional repression or silencing. In the mouse, loss of Suv proteins is associated with the spontaneous development of B-cell lymphoma. The association of Smads with Suv thus provides a mechanism for transcriptional silencing of genes regulated by TGF-beta signaling pathways that may be important in cancer. In this proposal, we will further characterize the interaction of Smad proteins with Suv at both the biochemical and functional level. In Specific Aim 1 we will determine the molecular details of the interaction of Suv and Smad proteins using SuvH1 and Smadl as prototypes. We will map the interaction domains on each protein and determine if likely transcriptional partners are present in the repression complex. In Specific Aim 2 we will characterize the functional significance of the interaction using reporter gene assays of a promoter known to be repressed by BMP signaling. We will also determine the cis elements involved in specifying transcriptional repression and determine if Smads and Suv proteins interact on DNA using chromatin immunoprecipitation and other assays. These studies will provide the foundation into further analysis of the mechanism of Suv-Smad interaction in transcriptional silencing.

描述（由申请人提供）：这是响应PA 02-100“基因表达激素调节中的复合物形成”的R21申请。“TGF-β配体超家族通过受体丝氨酸-苏氨酸激酶传递信号，这些激酶使用称为Smads的可转位转录因子向下游传递信号。在细胞核中，Smads与DNA结合蛋白和转录辅因子结合来调节靶基因的表达。TGF-β和BMP信号传导的丧失对癌症具有重要意义，因为已经显示几种人类癌症在其发展过程中丧失了TGF-β信号传导能力，并且已经在至少一种遗传性癌症综合征中显示了BMP受体的突变。最近发现，靶基因转录调控的一个重要组成部分是阻遏，而阻遏的丧失对正常发育和体内平衡是有害的。我们已经确定了BMP调节的Smad蛋白与Suv家族的组蛋白甲基转移酶的关联。这些蛋白质甲基化赖氨酸9上的组蛋白H3并引起转录抑制或沉默。在小鼠中，Suv蛋白的丢失与B细胞淋巴瘤的自发发展相关。因此，Smads与Suv的关联提供了一种由TGF-β信号通路调节的基因转录沉默的机制，这在癌症中可能是重要的。在这个提议中，我们将进一步表征Smad蛋白与Suv在生化和功能水平上的相互作用。在具体目标1中，我们将使用SuvH 1和Smadl作为原型来确定Suv和Smad蛋白相互作用的分子细节。我们将绘制每个蛋白质上的相互作用结构域，并确定是否可能的转录伴侣存在于阻遏复合物中。在具体目标2中，我们将使用已知被BMP信号抑制的启动子的报告基因测定来表征相互作用的功能意义。我们还将确定参与指定转录抑制的顺式元件，并确定Smads和Suv蛋白是否使用染色质免疫沉淀和其他测定在DNA上相互作用。这些研究为进一步分析Suv-Smad相互作用在转录沉默中的作用机制奠定了基础。