Conditional expression of apical membrane antigen 1 in Plasmodium falciparum shows it is required for erythrocyte invasion by merozoites.
Bottom Line: DiCre-mediated excision of the loxP-flanked Pfama1 gene results in approximately 80% decreased expression of the protein within one intraerythrocytic growth cycle.This reduces growth by 40%, due to decreased invasion efficiency characterized by a post-invasion defect in sealing of the parasitophorous vacuole.These results show that PfAMA1 is an essential protein for merozoite invasion in P. falciparum and either directly or indirectly plays a role in resealing of the red blood cell at the posterior end of the invasion event.
Affiliation: The Walter and Eliza Hall Institute of Medical Research, Melbourne, Vic., 3052, Australia.Show MeSH
Related in: MedlinePlus
Mentions: The gene encoding PfAMA1 is refractory to genetic ablation via conventional knockout strategies (Triglia et al., 2000) and consequently we constructed a P. falciparum line in which it was placed under conditional regulation. To do this we simultaneously disrupted the endogenous Pfama1 gene, in the W2mef line by single recombination, with the plasmid pAMA1-loxP allowing complementation with a transfected gene (encodes the antigenically distinct 3D7 allele) flanked with loxP sites (Fig. 1). The resulting W2mef/AMA1-loxP parasites were cloned by limiting dilution and the clones derived had two copies of the plasmid inserted into the Pfama1 gene resulting in two functional copies of the 3D7 allele (Figs 1 and 2A, Fig. S1).
Affiliation: The Walter and Eliza Hall Institute of Medical Research, Melbourne, Vic., 3052, Australia.