Integration of Lef/Tcf isoforms in regulatory networks involved in brain pattering

Lef/Tcf 同种型在参与大脑模式的调节网络中的整合

• 批准号: 5398464
• 负责人: Dr. Dietmar Gradl
• 金额: --
• 依托单位: Abteilung für Zell- und Entwicklungsbiologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2003
• 资助国家: 德国
• 起止时间: 2002-12-31 至 2008-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5398464?language=en
• 关键词: Integration; Lef; Tcf; isoforms; regulatory

As nuclear mediators of the oncogenic Wnt/b-catenin signaling pathway, the sequence specific HMG-box transcription factors of LEF/TCF family graduate important decisions in embryogenesis and in the development of malignat carcinoma. In the previous funding period we characterized the different properties of the individual LEF/TCF family members in Xenopus by identifying several repressive and activating domains within these molecules. The different expression patterns and properties of XTCF3, XTCF-4 A, B, C and XLEF-1 implicate a function of these transcription factors as modifiers of the cellular response in canonical Wnt-signaling. To test this hypothesis we will focus on the role of individual LEF/TCF transcription factors in patterning the brain where they exhibit distinct non-overlapping expression profiles. To identify the function of single transcription factors we will apply antisense morpholino injections in combination with ectopic expression of the other LEF/TCF family members. Altered patterning of the brain will be followed by marker gene expression. These experiments will be performed with whole embryos as well as with neuralized animal cap explants. In a second part we will further clear up how the different properties of the transcription factors are layed down in their structure. In search for specific interaction partners we will perform Tandem-Affinity Purification (TAP) using double tagged fusion proteins of important LEF/TCF domains followed by MALDI-TOF analyses of the coprecipitates. Interesting interaction partners will be isolated and further caracterized. Their regulative function in canonical Wnt-signaling will be studied by double axis formation and reporter gene assays, and predominantly in brain patterning if they are co-expressed with LEF/TCF transcription factors in certain brain compartiments.

作为致癌 Wnt/b-catenin 信号通路的核介质，LEF/TCF 家族的序列特异性 HMG-box 转录因子在胚胎发生和恶性肿瘤的发展中发挥着重要作用。在之前的资助期间，我们通过识别这些分子内的几个抑制和激活结构域来描述爪蟾个体 LEF/TCF 家族成员的不同特性。 XTCF3、XTCF-4 A、B、C 和 XLEF-1 的不同表达模式和特性暗示这些转录因子作为典型 Wnt 信号传导中细胞反应的调节剂的功能。为了检验这一假设，我们将重点关注各个 LEF/TCF 转录因子在大脑模式中的作用，其中它们表现出不同的非重叠表达谱。为了鉴定单个转录因子的功能，我们将应用反义吗啉注射与其他 LEF/TCF 家族成员的异位表达相结合。大脑模式的改变将伴随着标记基因的表达。这些实验将使用整个胚胎以及神经化的动物帽外植体进行。在第二部分中，我们将进一步阐明转录因子的不同特性是如何在其结构中确定的。为了寻找特定的相互作用伙伴，我们将使用重要的 LEF/TCF 结构域的双标记融合蛋白进行串联亲和纯化 (TAP)，然后对共沉淀物进行 MALDI-TOF 分析。有趣的互动伙伴将被隔离并进一步特征化。它们在经典 Wnt 信号传导中的调节功能将通过双轴形成和报告基因测定来研究，如果它们与某些脑区室中的 LEF/TCF 转录因子共表达，则主要在脑模式中进行研究。