A systems biology study of E2F and NF-kappaB cross-talk

我们以前曾使用显微镜研究重要的应激信号系统，称为核因子-kappaB，它几乎存在于所有哺乳动物细胞类型中。这一系统已被证明对关节炎和哮喘等炎症性疾病以及癌症都很重要。我们发现，核因子-kappaB，使用进入和离开细胞核的频率来确定哪些基因被激活。我们已经发现，一种名为E2F的转录因子(一种与其他基因结合并控制其开启的蛋白质)与NF-kappaB信号系统相互作用。众所周知，E2F是允许细胞在细胞分裂之前(在称为细胞周期的重复过程中)开始复制DNA的主要开关。似乎当细胞内有高水平的核因子-kappaB信号时，E2F就会停止这种信号。我们发现，E2F在细胞核中含有一种名为p65的关键核因子-kappaB蛋白，而它通常位于细胞质中。当核因子-kappaB被刺激时，高水平的E2F的存在会导致在核因子-kappaB运动开始振荡之前的延迟。我们希望研究1)E2F和NF-kappaB蛋白在细胞分裂的不同阶段的水平，以及这些蛋白中的哪一种在细胞中相互结合。为此，我们将使用基于质谱学的准确蛋白质浓度测量，并将使用显微镜或抗体测量蛋白质相互作用，这些抗体允许相互结合的蛋白质沉淀。在整个过程中，我们将使用和开发这个复杂系统的数学模型。我们已经建立了核因子-kappaB系统的数学模型，我们将把这些模型与现有的细胞周期数学模型联系起来。数学模型将被用来预测和解释实验结果。因此，这项工作将允许对炎症信号的基本过程(核因子-kappaB)和细胞分裂(E2F)之间的关系有一个新的理解，这对于理解正常和疾病相关的炎症和细胞分裂将是重要的。

We have previously used microscopy to study the important stress signalling system called NF-kappaB, which is present in virtually all mammalian cell types. This system has been shown to be important in inflammatory diseases such as arthritis and asthma, as well as cancer. We showed that NF-kappaB, uses the frequency of movements into and out of the nucleus to determine which genes are switched on. We have found that a transcription factor (a protein which binds to and controls the switching on of other genes) called E2F interacts with the NF-kappaB signalling system. E2F is well known as the principal switch that allows cells to begin to make another copy of their DNA prior to cell division (in a repeating process called the cell cycle). It seems that E2F stops an NF-kappaB signal when there is a high level of this protein inside cells. We found that E2F holds a key NF-kappaB protein called p65 in the nucleus, when it would normally be in the cytoplasm. When NF-kappaB is stimulated, the presence of a high level of E2F causes a delay before oscillations in NF-kappaB movement begin. We wish to investigate 1) the levels of E2F and NF-kappaB proteins at different stages of cell division and which of these proteins bind to each other in the cell. For this we will use mass spectrometry-based measurement of exact protein concentrations and will measure protein interactions using either microscopy or antibodies that allow the precipitation of proteins that bind to each other. Throughout this process we will use and develop a mathematical model of this complicated system. We have already built mathematical models of the NF-kappaB system and we will link these with existing mathematical models of the cell cycle. The mathematical models will be used to predict and interpret the experimental results. The work will therefore allow a new understanding of the relationship between the basic processes of inflammatory signalling (NF-kappaB) and cell division (E2F) which will be important for understanding normal and disease-related inflammation and cell division.