Fluorescence Imaging Group

Transcription is the process by which the DNA encoding a gene is read to produce an RNA transcript. This process is fundamental to gene expression, and involves hundreds of proteins acting in concert. Some of these proteins regulate the process, others produce the actual transcript, and still others modify the chromatin structure to facilitate the first two processes.

Our approach is to visualize this process in live cells.Our experimental system uses tandem copies of a promoter-reporter gene cassette integrated in a cell line containing a fluorescently tagged transcription factor. This strategy enables us to directly visualize transcription factor binding to its target site. This has proven successful in mammalian cells and is currently being developed in Saccharomyces cerevisiae.

Our work has shown that transcription factor interactions with their target is very dynamic. Namely, we discovered that the GFP-glucocorticoid receptor remains bound to its DNA template for only a few seconds. This raises fundamental questions about how the transcription machinery operates, and these questions are under study in the first project, dynamics of the transcription apparatus.

A principal tool of our work is live cell fluorescence microscopy which is utilized in our state-of-the-art Fluorescence Microscopy Facility. The techniques used here are derived from earlier cell motility studies by our group.