TABLE 2.
Mutability (lac revertants per 108 cells) of wild-type and dgt strains in MMR-proficient or MMR-deficient (mutL) backgroundsa
| Genotype | lac A·T→C·G | lac G·C→A·T | lac G·C→C·G | lac G·C→T·A | lac A·T→T·A | lac A·T→G·C |
|---|---|---|---|---|---|---|
| Wild type | 0.2 ± 0.1 | 1.6 ± 0.1 | 0.02 ± 0.02 | 3.4 ± 0.2 | 0.6 ± 0.1 | 0.03 ± 0.02 |
| dgt | 0.2 ± 0.1 | 3.6 ± 0.2 | 0.4 ± 0.1 | 1.0 ± 0.1 | 0.6 ± 0.1 | 1.2 ± 0.2 |
| mutL | 1.1 ± 0.2 | 147 ± 12 | 0.03 ± 0.03 | 14.3 ± 1.4 | 1.6 ± 0.3 | 14.1 ± 1.2 |
| dgt mutL | 1.1 ± 0.2 | 133 ± 36 | 2.0 ± 0.5 | 7.2 ± 0.8 | 1.6 ± 0.3 | 31.0 ± 1.5 |
a
Mutant frequencies were determined as described in Materials and Methods. The six different lac alleles used to measure the reversion frequency are indicated by the specific base pair substitution by which they revert (see text for details). The strains used were NR16942 to NR16947 (wild type), NR16948 to NR16953 (dgt), NR16897 to NR16902 (mutL), and NR17227 to NR17232 (dgt mutL) (Table 1).