TABLE 3.
Lac phenotypes of colonies and switch frequencies of agn′-lacZ-containing isolates with GATC mutations in an oxyR+ dam+ background and in the presence of the Dam-encoding plasmid pTP166
| agn43 sequence | Strain | Lac phenotypea (switch frequency) | Strain with pTP166 | Lac phenotypea |
|---|---|---|---|---|
| Wild type | MV198 | ON⇒OFF (2.5 × 10−3) | MV203 | ON |
| OFF⇒ON (8.7 × 10−4) | ||||
| GATC-I mutant | MV336 | ON⇒OFF (4.0 × 10−2) | MV342 | ON |
| OFF⇒ON (4.5 × 10−4) | ||||
| GATC-II mutant | MV310 | OFF | MV315 | ON |
| GATC-III mutant | MV289 | OFF | MV295 | ON |
| GATC-I, -II, -III mutant | MV353 | OFF | MV375 | OFF |
a
Cultures from ON colonies had LacZ activity ranging from 1,100 to 2,000 MU; those from OFF colonies had <20 MU of LacZ activity.