Figure 1.

Dynamic dissociation, re-association and redistribution of RNAP with the genome during osmotic stress. (A) Growth curve of CC72 in LB without (close circle) and with (open circle) osmotic stress in early-exponential phase. Red arrow indicates the time that osmotic stress was induced. Red and blue arrows indicate the time that samples were collected for imaging, ChIP-chip and transcriptome assays. Vertical bars represent standard deviations of three biological replicates. (B) The amount of RNA synthesized in LB without (close circle) and with (open circle) osmotic stress relative to time 0. The starting time of osmotic stress is designated as time 0. Vertical bars indicate the standard deviation of the mean for three independent experiments. (C) SR-SIM co-imaging of representative RNAP (green) and nucleoid (red) in the four typical phases. The scale bar represents 1 μm. (D) Genome browser representations of dynamic change in RNAP binding from LB to Na10, Na20 and Na45 with a moving average of 200 kb. Lower bar represents the E. coli genome with the locations of ori (light grey ellipse), ter (dark gray ellipse) and rrn regions (red circle). (E) Number of oligonucleotides with RNAP binding in each of the 10 kb bins. The coverage represents the proportion of oligonucleotides enriched in RNAP out of the number of total oligonucleotides. (F) Scatter plot of mean RNAP-binding signal intensity at Na10, Na20 and Na45 compared with LB. After normalizing the raw data, the relative intensity of RNAP binding was smoothed by a moving median of 400 bp. Then, the corresponding binding intensities of all probes in each 10 kb bin were averaged as the ‘mean RNAP binding’. Each dot represents a 10 kb bin. y = x (black diagonal) is shown to represent the same RNAP binding compared with LB. The smooth colored curves represent loess fit with a span of 0.75. The P values by two-sided t-test between LB and Na10, Na20 or Na45 are shown.