TABLE 2.

Recombinational DNA repair, cell viability, and homologous recombination in recD mutants lacking activities of various exonucleases

		Relative cellular viability	Relative fractional survival		λ zygotic induction in Hfr cross	Relative recombination frequency
Strain	Description		UV (20 J m−2)	γ (150 Gy)		Pro+ transconjugants	Pro+ transductants
DE100	RecD−	1.0a	1.0	1.0	1.0	1.0	1.0
DE1050	RecD− ExoI−	0.85	1.0	0.68	0.95	0.22	0.73
DE1051	RecD− ExoX−	1.0	1.18	1.20	0.91	1.16	1.14
DE1052	RecD− ExoVII−	0.98	0.95	0.93	0.93	1.07	1.28
DE1057	RecD− ExoX− ExoVII−	0.96	0.82	0.62	0.79	0.97	1.18
DE1055	RecD− ExoI− ExoX−	0.68	0.98	0.76	0.76	0.0089	0.31
DE1056	RecD− ExoI− SbcD−	0.83	0.96	0.61	ND	ND	ND
DE1054	RecD− ExoI− ExoVII−	0.81	0.33	0.29	1.0	0.78	1.07
DE1059	RecD− ExoI− ExoVII−ExoX−	0.72	0.13	0.24	0.92	0.80	1.13
DE1060	RecD− ExoI− ExoVII− SbcD−	0.56	0.09	0.12	ND	ND	ND
DE1061	RecD− RecJ−	0.68 (0.86b; 1.0cd)	0.00058 (0.0007c; ∼0.002b; ∼0.07d)	0.18 (∼0.3d)	0.91 (0.74c)	0.135 (0.012c; 0.28d; 0.34b)	0.75 (0.07c)
DE1062	RecD− RecJ− ExoI−	0.20	0.00008	0.00024	0.68	0.0063	0.13
DE1063	RecD− RecJ− ExoVII−	0.009	0.00004	<0.0001	0.62	0.00051	<0.001
DE101	RecB−	0.39	0.0013	0.0018	0.89	0.0051	0.0036

ND, not determined.

^aCellular viability of 1.0 corresponds to 1.3 × 10⁸ recD colony-forming units ml⁻¹ at an OD₆₀₀ of 0.3. UV and γ-survival of 1.0 correspond to 21 and 75 survivors/100 irradiated recD cells, respectively. Frequency 1.0 for λ zygotic induction corresponds to 41 infective centers/100 IRB100 donors. Recombination frequency of 1.0 corresponds to 22 Pro⁺ transconjugants/100 Hfr3000 donor cells and 6 × 10⁻⁵ Pro⁺ transductants per P1 plaque-forming unit. Recombination efficiency is corrected for the viability of the recipients. All values are averages of at least three independent experiments except for zygotic induction in Hfr crosses, which are averages of two determinations.

^bReported by Lloyd et al. (1988).

^cReported by Lovett et al. (1988).

^dReported by Ivančić-Baće et al. (2005).