MRE Luciferase Reporter Lentiviruses (Heavy Metal Stress) are replication incompetent, HIV-based, VSV-G pseudotyped lentiviral particles that are ready to transduce nearly all types of mammalian cells, including primary and non-dividing cells. These viruses contain a firefly luciferase reporter driven by multiple copies of MRE (metal response elements) located upstream of the minimal TATA promoter, and a puromycin selection marker (Figure 1). After transduction, transcription mediated by MRE can be monitored by measuring luciferase activity.