Stage-dependent gene expression of transporters throughout the intraerythrocytic cycle of P. falciparum. (a) A putative transporter of the MFS family; (b) the three P. falciparum members of the sugar porter family (a subfamily of the MFS). The PFB0210c gene encodes the P. falciparum hexose transporter, PfHT1 . RT-PCR was conducted to semi-quantify the level of gene expression in ~1.5 × 104 parasitized cells at each growth stage. Relative expression (y-axis) is the ratio of the density of the band from the PCR product at each time point in the life cycle relative to that at the time point giving the largest yield of PCR product. Ratios calculated from replicate gels from the same PCR were averaged before the data from the two time courses (carried out approximately 4 months apart and each consisting of ≥ 2 PCRs) were combined to give the mean ± S.E. For comparison, the relative amount of total RNA in the parasitized cell over the same growth stages is also presented (dotted line).