Fig. 3

Direct observation of the movement of a non-membrane protein gene locus by transcription of E. coli RNAP. a A schematic of the gene system used to detect location of the lacZ gene locus transcribed by E. coli RNAP (left panel). Six repeats of TetO (6xTetO) were inserted downstream of the lacZ gene or mCherry gene transcribed by E. coli RNAP. TetR-eYFPs bound to the TetO array were detected as a fluorescent spot (middle panel). The localization error was 30 nm. Scale bar, 1 μm. b Quantitative analysis of the movement of the lacZ gene locus. The lacZ gene locus moved to the nucleoid periphery after IPTG induction (lacZ-6xTetO strain, blue squares) (>1500 spots). Movement of the lacZ gene locus following the RBS deletion (lacZ-6xTetO_ΔRBS strain, gray circles) was not observed (>800 spots). Data represent mean ± s.d. obtained from three independent experiments. Each point represents independent measurement. c Quantitative analysis of mCherry gene locus movement. Movement of the mCherry gene to the nucleoid periphery was observed after IPTG induction (mCherry-6xTetO, red squares) (>940 spots). Data represent mean ± s.d. obtained from three independent experiments. Each point represents independent measurement. d, e Comparison of gene locus movement with and without the RBS at 24°C (d) and 37°C (e). Average relative x-positions of gene loci were obtained without IPTG (repressed) and 5 min after adding IPTG (induced). Blue bar, lacZ-6xTetO, and gray bar, lacZ-6xTetO_ΔRBS. Bar and error bars represent mean ± s.d. from three independent experiments. Each point represents independent measurement