FIG. 5.

HAV IRES-dependent translation in Huh-T7 and BT7-H cells, which constitutively express T7 RNA polymerase and are derived from Huh-7 and BSC-1 cells, respectively. (A) Organization of the dicistronic plasmids, pLuc-wt-RLuc and pLuc-p16-RLuc, that express F-Luc from the 5′ reading frame, which serves as a transfection and transcription control, and R-Luc from the 3′ reading frame under the translational control of the HAV IRES placed within the intercistronic space. This transcription unit is under the control of the T7 promoter. (B) Relative HAV IRES activity in BT7-H and Huh-T7 cells. Values are ratios between F-Luc and R-Luc activities, or the relative activity of HAV IRES in each cell line. Open bars, wild-type IRES; solid bars, cell culture-adapted HM175/p16 IRES (42). Absolute values of F-Luc activity ranged from 3.2 to 11 light units.