Table 2.
Commonly used counter-selectable markers and associated selections for homologous recombination in bacteria
| Marker | Counterselection | Reference |
|---|---|---|
| sacB | Sucrose | [101] |
| upp | 5-Fluorouracil | [102] |
| hpt | 8-Azahypoxanthine, others | [103] |
| tdk | 5-Fluorodeoxyuridine | [104] |
| pyrF/ura3a | 5-Fluoroorotic acid | [105] |
| pheS*(A294G) | p-Chloro-phenylalanine | [106] |
| codA | 5-Fluorocytosine | [107] |
| Inducible mazF | N/A; expression is toxic | [95] |
| galK | 2-Deoxygalactose | [108] |
| apt | 2-Fluoroadenine | [109] |
| rpsL(strA) | Streptomycin | [110] |
| tetARa | Fusaric acid | [111] |
| thyA | Trimethoprim | [112] |
| Inducible ccdB | Expression is toxic | [113] |
| oroP | 5-Fluoroorotate | [114] |
| pta-ack | Chloroacetate | [115] |
aCan be used as a positive selectable marker with uracil prototrophy and tetracycline resistance, respectively