When I was looking for a postdoc position, I came across a 2011 paper by Larson et al. in Science, which described the direct observation of transcription as it occurred in living cells. I was immediately inspired: no averaging between cells, no inference, no snapshots, but directly measuring the instantaneous transcription of an endogenous gene in a single cell. I could see endless possibilities for using this technique to study the mechanisms of gene regulation, which is why I joined the group of Daniel Larson, the first author of this paper, who had just started his own lab at the National Cancer Institute in Bethesda.

Moreover, combining the quantitative measurement of transcription initiation with estimates of transcription factor search time suggested that the kinetics of transcription factor–DNA binding is the limiting factor of transcription initiation.