Figure 4
From: An internal ribosome entry site element directs the synthesis of the 80 kDa isoforms of protein 4.1R
The generation of the short protein 4.1R is not due to a cryptic promoter. A. Schematic representation of the plasmids used in the western blot analysis shown in B. The first plasmid contained the 4.1R cDNA 1' under the control of the CMV promoter, whereas the CMV promoter was eliminated from the second plasmid (1'ΔCMV). 4.1R proteins were tagged at the amino and carboxyl termini with FLAG and myc epitopes, respectively, to detect the exogenously expressed 4.1R proteins. B. Western blot of total protein extracts from COS-7 cells transfected with an empty plasmid (-) and from cells transfected with the indicated plasmids, revealed with the anti-myc and the anti-FLAG antibodies.