TABLE 2.
Transforming activities of JSRV and ENTV Env YXXM mutants in NIH 3T3 cells during prolonged culturea
| Env protein | Transformed foci per dish at week:
|
|||
|---|---|---|---|---|
| 2 | 3 | 4 | 5 | |
| Jenv-FLAG | 18 ± 3.6 | 34 ± 10 | TMTC | |
| Jenv-Y590F-FLAG | 0 | 1.5 ± 0.7 | 3 ± 2.6 | 5 ± 3.1 |
| Jenv-Y590D-FLAG | 0 | 1 ± 0 | 1 ± 0 | 1.5 ± 0.6 |
| Jenv-Y590C-FLAG | 0 | 0 | 1.5 ± 0.6 | 2.6 ± 0.6 |
| Jenv-M593A-FLAG | 8 ± 3.6 | 15 ± 4.5 | 24 ± 2.8 | TMTC |
| Jenv-M593T-FLAG | 6 ± 1.4 | 10 ± 4.7 | 14 ± 8.5 | TMTC |
| Jenv-M593E-FLAG | 0 | 0 | 0 | 3 ± 1.5 |
| FLAG-Eenv | 26 ± 8.7 | 47 ± 17 | TMTC | |
| FLAG-Eenv-Y590F | 14 ± 3.2 | 26 ± 2.1 | TMTC | |
| FLAG-Eenv-Y590,2,6F | 2 ± 0.7 | 2.5 ± 0.7 | 6 ± 2.5 | 6 ± 3 |
| 10A1 Env | 0 | 0 | 0 | 0 |
a
NIH 3T3 cells were transfected with 10 μg of each plasmid encoding the indicated Env proteins. The next day, cells were split 1:2 into 6-cm dishes in medium containing G418 (750 μg/ml, active concentration). After 7 to 10 days of drug selection, cells were fed with DMEM plus 5% FBS every 3 to 4 days, and transformed foci were counted at the indicated times (foci per 5 μg of DNA). Results are means ± standard deviations of two independent experiments. TMTC, too many to count.