Figure 5

Selection of parasite transfectants expressing negative or positive selectable markers directed by Pfnek-4 promoter. A, In vitro growth rate of 3D7 parasite transfectants expressing the Saccharomyces cerevisiae cytosine deaminase-uridylphosphoribosyltransferase fusion gene (ScCDUP) driven by Hsp86 (pScCDUP_Hsp86) or Pfnek-4 (pScCDUP_Pfnek-4) 5’ flanking regions, in presence (●) or absence (○) of prodrug 5-FC (1 μM). B, In vitro growth rate of untransformed 3D7 (3D7 control) and 3D7 parasite transfectants expressing the human dihydrofolate reductase (hDHFR) gene driven by Pfnek-4 5’ flanking region (phDHFR_Pfnek-4), in presence (■) or absence (□) of WR22910 (5 nM). Parasitaemia (mean of duplicate cultures) were determined daily by Giemsa-stained blood smears and parasite cultures >3% parasitaemia were diluted to 1%-parasitaemia.