Figure 3

A conserved motif of the elongation factor one alpha ( ef-1α ) intergenic region can increase the P. vivax ef-1α promoter strength. A. Upper diagram represents the ef-1α intergenic region in Plasmodium. The Gibbs matrices of the Regulatory Sequence Analysis tools [31] was used to search conserved motifs in the ef-1α intergenic region of P. falciparum – Pf, P. reichenowi – Pr, P. berghei – Pb, P. yoelii – Py, P. knowlesi – Pk and P. vivax – Pv. A conserved identical motif – GCATAT – was observed in all species excepting P. vivax where positions 4 and 6 are degenerate. Position and orientation of the EF motif along the intergenic regions are shown. B. Reporter plasmids constructed to functionally characterize the motif. The EF motif was cloned into Hind III restriction site of pPv-EF(B) to create plasmids pPv-EF(B)-HFE and in the Nde I of this one to create pPv-EF(B)-HNFE. Pv ef-1α IR – P. vivax ef-1α intergenic region; LUC – luciferase; DT 3' – P. berghei dihydrofolate reductase 3' UTR. The EF motif is represented by black squares. C. Transient transfection in P. falciparum. Reporter plasmids were transiently transfected in P. falciparum. Reporter expression values are represented relative to pPv-EF(B). Negative control (-) refers to luminescence measures of the substrate alone or plasmid with luciferase and malaria 3' UTR but no promoter. Linear scale was used. Values represent the mean of at least three independent experiments done with two or three different DNA preparations. Bars represent standard deviations. Scale is in kilobase-pairs (kb).