Figure 3.

Involvement of multiple LigD under stress conditions. Similar experiments as in Figures 1 and 2 were performed using competent cells prepared from heat stressed exponential phase cultures (red). (A) Ligases involved with Ku2: all ligD mutations are in a Ku+ background. Values obtained with the WT strain are the same as in Figure 2 and are indicated as references. (B) Ligases involved with Ku3–4: all ligD mutations are introduced in a ku1 ku2 mutant background. All results shown are the means (±SEM) of the plotted values, obtained from independent experiments (n ≥ 3). The absence of value means that no colony was obtained (detection threshold indicated on the graph). Statistical analyses were performed using a one-way analysis of variance (see Supplementary Table S4 for detailed statistical analysis results). The Bonferroni posttest was used to carry out the indicated comparisons (*P< 0.05; **P < 0.01; ***P < 0.001).