Measurement of gene regulation in individual cells reveals rapid switching between promoter states

Abstract

Stochastic properties of phage promoter Full understanding of regulated gene expression requires characterization of stochastic variation in the activity of individual promoters. To avoid cell-to-cell variability and variation between the activity of specific gene copies, Sepúlveda et al. investigated the behavior of the lysogeny maintenance promoter of phage lambda in individual Escherichia coli cells. They measured the concentration of transcription factor and the actual number of mRNAs produced, and used mathematical modeling to discern the stochastic activity of the regulated promoter. The promoter underwent switching between configurations that occurred more rapidly than the lifetime of mRNA molecules produced, and individual copies of the same gene functioned independently in the same cell. Such studies can reveal new aspects of systems that have been well studied by more conventional techniques. Science , this issue p. 1218