Figure 1.

RecD is required for cells to survive certain forms of DNA damage. (A) Cultures of strains containing the DNA palindrome or not were serially diluted and grown overnight under either conditions where SbcCD was induced (SbcCD⁺), or repressed (SbcCD⁻). Colony formation at higher dilution (lower OD₆₀₀) indicates increased cellular viability. (B, D) Quantitative assessment of the number of viable cells (the number of colony forming units per 1 ml of culture normalised to an optical density at 600 nm of 1) following 60 min of exponential growth with (B) SbcCD either expressed or not; (D) I-SceI either expressed or not. (C) Cultures of strains containing the DNA palindrome or not were serially diluted and grown overnight under either conditions where SbcCD was repressed following, or not, exposure to ultraviolet (UV)-light. Data for A) and C) are representative experiments; data for B) and D) are represented as mean ± S.E.M., n = 3. No difference in viability was detected between the recD⁺ I-SceI⁺I-SceI_cs⁺ and recD⁻ I-SceI⁺I-SceI_cs⁺ samples (two-sample t test, P = 0.68). See also Supplementary Figure S1.