title: Improved transfection and new selectable markers for the rodent malaria parasite Plasmodium yoelii.
abstract: The rodent malaria Plasmodium yoelii is a useful model to study protective immunity to pre-erythrocytic stages of infection, pathogenesis of erythrocytic stages, and vaccine development. However, the utility of the P. yoelii model system has not been fully realized because transfection and genetic manipulation methodologies for this rodent species are less developed than that of another rodent species Plasmodium berghei. Here we report improved transfection efficiency using the AMAXA nucleofector system compared to conventional transfection methodologies. We also show that heterologous promoters from P. berghei can be used to drive expression of a green fluorescent protein (GFP) reporter protein in P. yoelii. In an effort to develop additional selectable markers for this parasite, we also tested positive selectable markers that have been used successfully in P. falciparum and P. berghei. Human dihydrofolate reductase (hdhfr) and Toxoplasma gondii dihydrofolate reductase-thymidylate synthase (Tgdhfr-ts) conferred drug resistance to WR99210 and pyrimethamine, respectively, when introduced as episomes. These improvements should make genetic manipulation of P. yoelii more amenable and facilitate further studies of host-parasite interactions using this attractive rodent model.
authors.affiliation: Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
authors.forename: Artemio M
authors.initials: AM
authors.lastname: Jongco
authors.forename: Li-Min
authors.initials: LM
authors.lastname: Ting
authors.forename: Vandana
authors.initials: V
authors.lastname: Thathy
authors.forename: Maria M
authors.initials: MM
authors.lastname: Mota
authors.forename: Kami
authors.initials: K
authors.lastname: Kim
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000494:pharmacology; D004195:Disease Models, Animal; D004351:Drug Resistance; D018274:Electroporation; D005260:Female; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D008288:Malaria / Q000469:parasitology; D051379:Mice; D008807:Mice, Inbred BALB C; D018512:Parasitemia; D010957:Plasmids / Q000235:genetics; D010962:Plasmodium berghei / Q000235:genetics; D010967:Plasmodium yoelii / Q000187:drug effects / Q000235:genetics*; D011401:Promoter Regions, Genetic; D011739:Pyrimethamine / Q000494:pharmacology; D011994:Recombinant Proteins / Q000032:analysis / Q000235:genetics; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics / Q000378:metabolism; D013940:Thymidylate Synthase / Q000235:genetics / Q000378:metabolism; D014162:Transfection / Q000379:methods*
chemical_list: D000962:Antimalarials; D011994:Recombinant Proteins; D049452:Green Fluorescent Proteins; D013762:Tetrahydrofolate Dehydrogenase; D013940:Thymidylate Synthase; D011739:Pyrimethamine