Single molecule approaches to transcription factor kinetics in living cells.

Quantitative modeling of intracellular processes often requires information about intracellular rate constants as well as the concentrations of low abundance species in individual cells. Single molecule imaging techniques offer not only new ways for obtaining such information but also the possibilities to test model-based hypotheses that have previously been out of reach for experiments. In this review we highlight some advantages of single molecule techniques and exemplify by their capability to help understanding how transcription factors find their chromosomal binding sites in bacterial cells.