Tissue-specific regulation of gene expression by Wnt/beta-catenin signalling

Wnt/β-连环蛋白信号传导对基因表达的组织特异性调控

• 批准号: BB/I003746/1
• 负责人: Stefan Hoppler
• 金额: $ 52.07万
• 依托单位: University of Aberdeen
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2011
• 资助国家: 英国
• 起止时间: 2011 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FI003746%2F1
• 关键词: Tissue; specific; regulation; gene; expression

One of the most important questions in biology is to explain how our body is built during embryogenesis. The many cells in the embryo communicate with each other (cell-to-cell signalling), initially to arrange the orientation of the general body plan and eventually to regulate formation of specialised cells (cell differentiation). This process does not end at birth, since many organs need to be repaired and tissues regenerated in the adult by continued formation of such specialised cells. The same cell-to-cell signalling pathways regulate this process in the adult as in the embryo. Defects in these signalling mechanisms lead to birth defects in embryos and in adults to diseases such as cancer. We already have a fair understanding of the individual linear cell-to-cell signalling mechanisms. They function to switch on or switch off genes, which issue instructions (called RNA) to build particular components that different cells need to form functional organs. These RNA instructions can be detected experimentally, but using conventional technology we can only look for specific RNA instructions. New state-of-the-art deep-sequencing methods allow the possibility of reading all the RNA instructions issued in a particular tissue. There is a fundamental gap in our current understanding of how individual cell-to-cell signalling mechanisms can so precisely control the exact combinations of RNA instructions needed in different cell types. How are specific genes switched on in particular cells? There are many different cell types but only few cell-to-cell signalling mechanisms, so the inputs from different cell-to-cell signalling mechanisms may be combined to produce the appropriate response. This integration could happen in several different ways, but the combination of switches regulating individual genes is obviously the most likely level for control. We will use new sequencing technology to read all the RNA instructions issued in a tissue to identify potentially regulated genes. We will confirm these candidate genes by verifying whether they are regulated by cell-to-cell signalling mechanisms in the correct tissue. Once confirmed, we will examine them for combination of switches through which these genes are regulated. We will be able to compare the whole complement of these genes in order to recognise whether they are mostly regulated by the same mechanisms, or whether different mechanisms apply to different genes. The insight gained will allow us to propose and then test possible molecular mechanisms that integrate cell-to-cell signalling to regulate genes in a specific tissue. Understanding how signalling mechanisms regulate genes will be relevant to understanding human and animal embryos, adult stem cells and cancer. However, this important issue is difficult to study directly in many of those systems. Xenopus embryos are ideal for tackling this fundamental question: they are accessible for experimental analysis; the large embryos provide sufficient material for sequence analysis; and we and others have intensively studied developmental processes in the early Xenopus embryo to suggest that at least one of the involved mechanisms involves integration of WNT and BMP signalling. Both of these signalling pathways are highly conserved between Xenopus and humans, and are important for embryogenesis, stem cells and cancer. Our pilot experiments show that our experimental approach is feasible and support our working hypothesis that combinatorial Wnt and BMP signalling regulates tissue-specific genes.

生物学中最重要的问题之一是解释我们的身体是如何在胚胎发育过程中建立的。胚胎中的许多细胞相互通信（细胞间信号传导），最初安排一般身体计划的方向，最终调节专门细胞的形成（细胞分化）。这一过程不会在出生时结束，因为许多器官需要修复，组织需要在成年后通过这种特殊细胞的持续形成而再生。同样的细胞到细胞的信号传导途径在成人和胚胎中调节这一过程。这些信号传导机制的缺陷导致胚胎的出生缺陷和成年人的疾病，如癌症。我们已经对单个线性细胞间信号传导机制有了相当的了解。它们的功能是打开或关闭基因，基因发出指令（称为RNA）来构建不同细胞形成功能器官所需的特定组件。这些RNA指令可以通过实验检测到，但使用常规技术，我们只能寻找特定的RNA指令。新的最先进的深度测序方法允许阅读特定组织中发出的所有RNA指令。我们目前对单个细胞间信号传导机制如何精确控制不同细胞类型所需的RNA指令的确切组合的理解存在根本性的差距。特定的基因是如何在特定的细胞中启动的？有许多不同的细胞类型，但只有很少的细胞间信号传导机制，因此来自不同细胞间信号传导机制的输入可以组合以产生适当的反应。这种整合可能以几种不同的方式发生，但调节单个基因的开关组合显然是最有可能的控制水平。我们将使用新的测序技术来读取组织中发出的所有RNA指令，以识别潜在的调控基因。我们将通过验证这些候选基因是否在正确的组织中受到细胞间信号传导机制的调控来确认它们。一旦得到证实，我们将检查它们的开关组合，通过这些开关调节这些基因。我们将能够比较这些基因的整个互补序列，以识别它们是否主要由相同的机制调节，或者不同的机制是否适用于不同的基因。获得的洞察力将使我们能够提出并测试可能的分子机制，这些机制整合了细胞间信号传导以调节特定组织中的基因。了解信号传导机制如何调节基因将有助于了解人类和动物胚胎、成体干细胞和癌症。然而，这一重要问题很难在其中许多系统中直接研究。非洲爪蟾胚胎是解决这一基本问题的理想选择：它们可用于实验分析;大型胚胎为序列分析提供了足够的材料;我们和其他人深入研究了早期非洲爪蟾胚胎的发育过程，表明至少有一种相关机制涉及WNT和BMP信号的整合。这两种信号通路在非洲爪蟾和人类之间高度保守，对胚胎发生、干细胞和癌症都很重要。我们的试点实验表明，我们的实验方法是可行的，并支持我们的工作假设，组合Wnt和BMP信号调节组织特异性基因。

项目成果

Genome-wide analysis of canonical Wnt target gene regulation in Xenopus tropicalis challenges ß-catenin paradigm.

热带非洲爪蟾典型 Wnt 靶基因调控的全基因组分析挑战了连环蛋白范式。

• 发表时间: 2017
• 作者: []