Figure 1.
Schematic of Ad-CMV-D2R80a-IRES-HSV1-sr39tk–mediated gene expression. A CMV promoter drives expression of a single mRNA containing D2R80a and HSV1-sr39tk cistrons, separated by an EMCV IRES. Upstream cistron (D2R80a) and downstream cistron (HSV1-sr39tk) are translated by ribosome binding to 5′cap and IRES, respectively. Translated product of D2R80a (D2R80A) binds to [18F]-FESP mainly on cell membrane, whereas translated product of HSV1-sr39tk (HSV1-sr39TK) phosphorylates [18F]-FHBG and traps it intracellularly.