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
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Mentions: The amount of Pfama1 gene excision in the B4 and 2F9 populations was between 70–92% and we next determined the corresponding level of PfAMA1 protein expression when Cre recombinase activity was induced by rapamycin. Schizont-stage parasites were analysed by immunoblot using α-3D7 AMA1 antibody. There was approximately 81% knockdown of AMA1 protein levels across the four time points when compared with untreated parasites (Fig. 4A–C). Expression of other invasion proteins such as PfRh4, RON4 and EBA175 was unaffected (Fig. 4D). This level of PfAMA1 protein knockdown correlated with the level of Pfama1 gene excision mediated by DiCre.
Affiliation: The Walter and Eliza Hall Institute of Medical Research, Melbourne, Vic., 3052, Australia.