Table 1.
Counterparts in B. subtilis and eukaryotes of E. coli functions related to chromosomal DNA replication and repair.
Figure 1.
Features of oriC-initiated replication in E. coli.
(A) Depiction of oriC, TerA, TerB and TerC loci on the 100 minute long circular E. coli chromosome, and of the clockwise and counterclockwise replichores; locations of the seven other Ter sites are also shown. (B) Schematic depiction of the copy number gradient, from oriC to Ter, created by the different extents to which replication forks have progressed on a single replichore in individual cells of an asynchronously dividing population. Aggregate copy numbers at the indicated positions are given at the bottom, but these are only illustrative and not to scale.
Figure 2.
Model of bilateral fork reversal reaction at a site where oncoming replisomes meet during replication termination.
Figure 3.
Predicted copy number distribution patterns for different categories of replication events in recG or rnhA mutants.
For all curves, positions of oriC, TerA, and TerC or TerB (TerC/B), are marked by the interrupted vertical lines; and copy number values are plotted on a linear instead of log scale to enable comparison with curves shown in Rudolph et al. [41]. (A–C) Three categories of replication events are shown, comprising those with forks initiated, respectively, (i) at oriC, DnaA-mediated (60%); (ii) on the counterclockwise replichore at various locations, R-loop mediated (20%); and (iii) on the clockwise replichore at various locations, R-loop mediated (20%). An individual cell in the population may harbor more than one category of event (see text). On the right in each of the three panels is a schematic depiction of progression of forks, each beginning at a solid circle and progressing to the position of arrowhead; in panels B and C, terminus region chromosomal DNA degradation (proximal to the sites of fork arrest at Ter) is shown as interrupted lines on the arcs, but retrograde fork advancements towards oriC (which are expected to occur at low efficiency [27], [54]) are not marked. On the left in each of the three panels is shown the expected copy number distribution for that category. (D) Expected copy number distribution for the entire cell population, obtained by summation of the distributions shown in panels A–C. (E) Expected copy number distribution for recG or rnhA mutant lacking oriC-initiated replication.