Summary of the in vivo activity of different mutated enhancer constructs
| Mutated site enhancer . | Wild-type sequence . | Mutant sequence . | TG . | EC . | ET . |
|---|---|---|---|---|---|
| wt | wt | wt | 15 | 6 | 4 |
| GATA bp 43 | AGATAC | AGgggC | 10 | 3 | 3 |
| GATA bp 72 | TGATAA | TGgggA | 9 | 0 | 4 |
| GATA bp 264 | GGATAC | GGgggC | 9 | 5 | 2 |
| SCL/Tal-1 bp 232 | TCAGAT | TCcccT | 12 | 7 | 6 |
| SCL/Tal-1 bp 358 | GCAGAT | GCcccT | 11 | 5 | 5 |
| Ets bp 308 | AGGAAC | AcGcgC | 10 | 0 | 3 |
| Ets bp 260 | GTCCCG | GcgcgG | 13 | 4 | 0 |
| Mutated site enhancer . | Wild-type sequence . | Mutant sequence . | TG . | EC . | ET . |
|---|---|---|---|---|---|
| wt | wt | wt | 15 | 6 | 4 |
| GATA bp 43 | AGATAC | AGgggC | 10 | 3 | 3 |
| GATA bp 72 | TGATAA | TGgggA | 9 | 0 | 4 |
| GATA bp 264 | GGATAC | GGgggC | 9 | 5 | 2 |
| SCL/Tal-1 bp 232 | TCAGAT | TCcccT | 12 | 7 | 6 |
| SCL/Tal-1 bp 358 | GCAGAT | GCcccT | 11 | 5 | 5 |
| Ets bp 308 | AGGAAC | AcGcgC | 10 | 0 | 3 |
| Ets bp 260 | GTCCCG | GcgcgG | 13 | 4 | 0 |
The number of embryos is indicated. To exclude stage-specific effects, transgenic embryos from at least 2 different stages between E10 and E12 were analyzed. Wt indicates wild type; TG, number of transgenic embryos analyzed; EC, number of transgenic embryos showing endothelium-specific reporter gene expression; ET, number of transgenic embryos showing ectopic reporter gene expression. Embryos were transgenic for LacZ reporter gene constructs containing the 939-bp Flk-1 promoter and the 430-bp minimal enhancer bearing mutations in putative transcription factor binding sites. The position of putative transcription factor binding sites in the 430-bp enhancer is depicted in Figure 2.