Figure 1.

The structure of the insertional mutagen. The HIV1-based construct is shown as a provirus integrated collinearly with a host gene. The provirus is flanked by promoter-deficient LTRs (“dLTR”). The internal promoter (“TO-mCMV”) is composed of tet-operators and a minimal CMV promoter. In the presence of an active tetracycline trasnactivator protein, it drives expression of the red fluorescent protein mCherry (“mCherry”) and puromycin N-acetyl-transferase (“puro”). Utilization of a splice-donor site (“SD”) permits fusion with downstream exons. The proteins encoded by the hybrid transcript are produced as separate peptides due to the presence of picornavirus F2A sequences between the respective coding regions.