Imaging chromatin transitions using high performance microscopy

DNA序列编码的信息需要指定许多生物体，包括人类是已知的。这些信息以被称为基因的功能单位的形式存在，通常情况下，在特定的情况下，只使用基因的一个子集。了解基因是如何在适当的时间被激活和关闭的，是理解健康生物体如何正常发育以及疾病期间出现什么问题的关键挑战。基因激活的一个关键步骤是通过一种称为RNA聚合酶的蛋白质产生DNA基因的RNA拷贝。RNA聚合酶接近DNA的能力通常被DNA与蛋白质包装以形成称为染色质的浓缩结构所阻止。很明显，染色质在活化过程中的展开和随后的重折叠代表了重要的控制点。然而，了解在单个基因的调控过程中发生了什么在一定程度上受到现有实验技术的限制。在本提案中，我们建议使用高性能显微镜的最新发展来直接跟踪单个基因在关闭和打开时的运动。这种类型的视觉信息是非常有用的，提供了一个测量的程度，基因是解折叠，以及多久，他们在RNA合成过程中解折叠。我们希望我们所做的观察将有助于填补我们对大多数生物系统基本过程的理解中的空白。

The DNA sequence that encodes the information required to specify many organisms, including humans is known. This information exists as functional units referred to as genes, and it is normally the case that in a specific context only a subset of genes are used. Understanding how genes are activated and switched off at the appropriate times represents a key challenge to understanding how healthy organisms develop normally and what goes wrong during disease. A key step in the activation of genes is the generation of an RNA copy of the DNA gene by a protein called RNA polymerase. The ability of RNA polymerase to gain access to DNA is normally prevented by packaging of DNA with proteins to for a condensed structure termed chromatin. It is becoming apparent that the unfolding of chromatin during activation and the subsequent refolding represent important points of control. However, understanding what occurs during the regulation of individual genes is to some extent limited by the experimental techniques that are available.In this proposal we propose to use very recent developments in high performance microscopy to directly track the motion of a single gene both when it is switched off and when it is on. This type of visual information is very informative, providing a measurement of the extent that genes are unfolded and for how long they are unfolded during the course of RNA synthesis. We hope that the observations we make will help to fill gaps in our understanding of a process which is fundamental to most biological systems.