The paper:
J. Elf et al., "Probing transcription factor dynamics at the single-molecule level in a living cell," Science, 316:1191–94, 2007. (Cited in 65 papers)
The finding:
Using fluorescence imaging, a Harvard team led by Sunney Xie quantified the kinetics of the lac operon repressor protein in Escherichia coli in real time. They showed that the protein spends a few milliseconds weakly and nonspecifically bound to DNA, diffusing along the chromosome, then dissociates for a fraction of a millisecond. This cycle of unbinding and rebinding various DNA segments repeats for a few minutes until the protein encounters its specific target.
The background:
Xie's team used a pair of techniques—developed in-house in 2006—to track fluorescently labeled proteins in living cells. In their method, DNA-bound proteins glow like bright dots, while the fluorescence of proteins diffusing in cytoplasm gets lost in the background. Xie's group also visualized nonspecific DNA binding using short ...
