Imaging chromatin transitions using high performance microscopy

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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.