Probing gene expression in single live cells, one molecule at a time

PHYS 176

Jie Xiao, xiao@fas.harvard.edu1, Ji Yu2, and X. Sunney Xie, xie@chemistry.harvard.edu2. (1) Department of Biophysics and Biophysical Chemistry, Johns Hopkins University, 725 N Wolfe Street, 708 WBSB, Baltimore, MD 21205, (2) Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138
We directly observe in real time production of single protein molecules in individual E. coli cells. A membrane-targeting sequence was fused to the gene of a fast maturating yellow fluorescent protein (YFP) on the chromosome DNA under the control of the lac promoter. Gene expression in a repressed condition generates membrane-localized YFP molecules that can be detected with single molecule sensitivity. We report that protein synthesis occurs in randomly distributed bursts and that the number of protein molecules in each burst follows a geometric distribution. This assay leads to quantitative understanding of the working of gene expression in live cells.
 

Structural Determination, Refinement, and Modeling of Large Biomolecular Complexes
8:20 AM-11:35 AM, Tuesday, August 21, 2007 BCEC -- 157C, Oral

Division of Physical Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007