Figure 1.

Lack of Hda leads to an increased oriC-to-terminus ratio in exponentially growing cells. (A–D) Genomic DNA prepared from exponentially growing cells of strains (A) MG1655, (B) JC125 (MG1655Δhda:tet^R), (C) JC326 (MG1655ΔseqA:tet^R) and (D) JC126 (MG1655ΔdatA:kan^R) was analysed using microarrays containing 95% of Escherichia coli open reading frames. DNA from deletion-mutant cells was compared directly with log-phase DNA from the wild-type (wt) cells (MG1655). The ratios are represented on the y-axis as relative abundance on a base 2 logarithmic scale (log₂). The x-axis represents the chromosomal location of each ORF in map minutes, with oriC located in the centre of each plot at 0 min. The black lines are plots of smoothed values from a moving median. (E). The bar graph shows the log₂ ratio of oriC-to-terminus for wt and mutant cells, where each region was defined as a four-map-minute zone surrounding or diametrically opposed to oriC, respectively. Results are shown as the average±standard deviation (n=3).