The role of TFIIB phosphorylation in the transcriptional stress response

有机体的基因包含着生命所必需的信息。这些基因编码构成细胞结构的产物，并执行基本过程的功能。所有的生物体都利用某种机制来开启和关闭基因，这样它们编码的产物的丰度就可以得到调节。调节基因开启和关闭的机制从酵母到人类都是高度保守的，并且与细菌中的机制相似。所有生物都需要对环境的变化做出反应，比如压力。这就需要基因的全局性改变，从而使细胞结构或功能的改变能够发生，以应对新的情况。我们对新基因如何在压力下启动以及它们如何帮助应对这些变化的理解已经取得了很大进展。然而，在压力条件下，非生存所必需的基因被关闭，以保存需要用于应激反应的能量。这些基因的广泛沉默是如何实现的尚不清楚。我们一直在研究一种蛋白质，转录因子IIB (TFIIB)，它在基因表达中起着核心作用，存在于从酵母到人类的所有生物中。我们发现TFIIB通过添加磷酸盐进行修饰，这是在正常条件下开启的大多数基因表达所必需的。有趣的是，不需要TFIIB磷酸化的基因是对压力的反应所必需的。当细胞受到应激时，磷酸盐迅速从TFIIB中去除。这导致非必需基因的暂时关闭，但允许对应激反应重要的基因被打开。我们最近的研究结果表明，TFIIB的磷酸化是生物体对应激反应所需的重要控制点。在拟议的研究中，我们将；确定TFIIB磷酸化如何影响基因表达。这一系列的研究将帮助我们理解应激反应基因是如何被选择性地开启的。确定人类细胞中通过TFIIB磷酸化机制开启和关闭的所有基因。这些结果将帮助我们理解在细胞压力下是什么使基因开启或关闭。确定负责从TFIIB中添加和去除磷酸盐的酶。这将使我们了解当细胞受到压力时，TFIIB磷酸化的平衡是如何变化的。这些研究的完成将为应激条件下发生的基因控制事件提供重要的新见解。这一信息将为潜在地控制生物体对压力的反应提供机会，这将在农业和转基因生物体的药物生产中具有重要用途。

The genes of an organism contain the information that is necessary for life. The genes encode the products that make up the structure of cells and perform the functions for essential processes. All organisms utilise mechanisms to switch genes on and off so that the abundance of the products they encode can be regulated. The mechanisms that are deployed to regulate the turning on and off of genes are highly conserved from yeast to man, and are also similar to those see in bacteria. All organisms need to respond to changes in their environment, i.e. stress. This requires global changes in the genes that need to be switched on so that changes in cellular structure or function can take place to deal with the new conditions. Much progress has been made in our understanding of how new genes are switched on under stress and how they help to deal with the changes. However, under stress conditions, genes that are not necessary for survival are switched off so as to conserve energy that needs to be deployed for the stress response. How the extensive silencing of these genes is achieved is not understood.We have been studying a protein, Transcription factor IIB (TFIIB), that plays a central role in the expression of genes and is found in all organisms from yeast to man. We found that TFIIB is modified by the addition of phosphate and that this is required for the expression of most genes that are switched on under normal conditions. Intriguingly, the genes that do not require the phosphorylation of TFIIB are required for the response to stress.When cells are subjected to stress, the phosphate is rapidly removed from TFIIB. This leads to the temporary shut-down of non-essential genes, but allows the genes important for the stress response to be switched on. Our recent results suggest that the phosphorylation of TFIIB is an essential control point that is required for the response of an organism to stress. In the proposed study we will;1. Determine how phosphorylation of TFIIB affects gene expression. This line of investigation will help us understand how the stress response genes are selectively switched on.2. Determine all of the genes in human cells that are switched on and off by the TFIIB phosphorylation mechanism. These results will help us to understand what makes a gene switch on or off under cell stress.3. Determine the enzymes that are responsible for adding and removing the phosphate from TFIIB. This will allow us to understand how the balance of TFIIB phosphorylation changes when cells are subjected to stress.The completion of these studies will provide significant new insights into the gene control events that occur under stress conditions. This information will provide opportunities to potentially control an organisms response to stress, that will have important uses in agriculture and drug production in modified organisms.