Evidence for Sequential and Increasing Activation of Replication Origins along Replication Timing Gradients in the Human Genome
Figure 7
Size and replication time of individual TTRs in multiple cell types.
The time difference, Dt, between the early and the late side of each TTR detected at scale 100 kb is plotted along its length, Dx, for each of the TTRs (dots) for (A) BG02, a human embryonic stem cell line (7657 TTRs); (B) K562, a chronic myelogenous leukemia cell line (3638 TTRs); (C) BJ, normal fibroblasts (5266 TTRs); (D) GM06990 (4017 TTRs), (E) TL010, (2492 TTRs) and (F) H0287 (3237 TTRs), lymphoblastoid cell lines. By definition, the maximum replication speed of TTRs is 10 kb/min (dark blue line). Lines corresponding to 5 kb/min (turquoise) and 2 kb/min are also provided as a guide to the eye. The mean apparent replication speed, Dx/Dt, is indicated by a green line (BG02, 2.34 kb/min; K562, 3.77 kb/min; BJ, 3.24 kb/min; GM06990, 4.04 kb/min; TL010, 4.21 kb/min; H0287, 4.17 kb/min). The mean (orange dashed line) and maximum (purple dashed line) velocities of single forks measured by DNA combing in identical or comparable cell lines (see text) are indicated. Except for BG02, practically no TTR is found between the orange dashed line and the vertical axis.