Rat cardiac myocytes were transduced with one of four different sensor viruses (Figure 1) containing unique promoters: 2xHRE-mp, 6xHRE-mp, Myh6, and cytomegalovirus (CMV) fused with GAL4-ODD-p65. The same myocytes were also transduced with the 6UAS-luciferase effector virus. The CMV-luciferase virus was used as a positive control of maximal adenoviral gene transfer efficiency. (a) At 48 hours after transduction, promoter activity of each pair of viruses was assessed by luciferase assay. (b) The transcriptional activity of each set of DOSVS was also normalized to CMV-luciferase activity. In each graph, “+” is hypoxic and “−” is normoxic. Values are mean ± SEM. HRE, hypoxia-responsive element; NS, not significant; ODD, oxygen-dependent degradation domain.