Fig. 6.
Expression of Gam and LigA together increases survival of cells experiencing a chromosomal DSB. (A) The host strain was either RecA+ (SMR14353) or isogenic RecA− (ΔRecA; SB08), and experiments were conducted in either the exponential or stationary phase. Relative cell survival was scored by counting cfus under the indicated experimental conditions (+/− representing induction of relevant proteins), and normalized to the lowest cell count (∼105) obtained in any single experiment. (B) Repair junctions of chromosomal breaks in RecA− cells. Of the exponential phase genomes examined (n = 865), nearly 50% of all sequences (n = 426) were perfect repairs. Of the remaining, 28% (n = 240) had repair joints with no homology, 13% (n = 118) had joints with 1 nt of homology, and 9% (81) had joints between 2 nt and 7 nt of homology. The repair trend was similar in the stationary phase genomes (n = 1,240). Nearly 50% (n = 595) showed accurate repair, 27% (n = 341) repaired with no homology, 17% (n = 218) with 1 nt of homology, and the remaining 3% (n = 86) between 2 nt and 7 nt of homology. See SI Appendix, Fig. S5 for deletion sizes at the repair joints.