Epigenetic Silencing of Plasmodium falciparum Genes Linked to Erythrocyte Invasion
Figure 5
Invasion Phenotypes Associated with the Expression Status of Variantly Expressed Invasion-Related Genes
(A) Invasion phenotype of 3D7-A subclones. Values correspond to percent of invasion into untreated erythrocytes and are the average of three to four independent experiments, with 95% confidence interval. Expression of genes that vary in expression between the subclones is shown underneath. The signs + and − correspond to high or low expression relative to other subclones. N.D., not determined; Nm., neuraminidase; Tr., trypsin; Ch.Tr, chymotrypsin; Nm.+Tr, neuraminidase plus trypsin.
(B) Scheme of the plasmids transfected in 3D7-A parasites for the episomal expression of EBA-140.
(C) Western blot analysis of schizont extracts, as in Figure 2A. Lanes are 3D7-A, 3D7-B, or 3D7-A parasites transfected with the different plasmids, as indicated.
(D) RT-PCR analysis at different stages of the life cycle in 3D7-A (lanes A), 3D7-B (lanes B), and E140-1300-transfected 3D7-A (lanes Atr). The amount of stage-specific cDNA was controlled by amplification of the genes PF13_0275 (rings), PF10_0121 (trophozoites), and ama1 (PF11_0344) (schizonts).
(E) IFA of E140-1300-transfected 3D7-A schizonts. Top and lower panels are representative of 65% and 35% of EBA-175-positive schizonts, respectively. The inserts in the top panels are free merozoites. Scale bar = 5 μm.
(F) Invasion phenotype of E140-1300-transfected 3D7-A parasites compared to that of 3D7-A and 3D7-B. Values correspond to percent of invasion into untreated erythrocytes and are the average of two independent experiments, with 95% confidence interval.