title: A plastid segregation defect in the protozoan parasite Toxoplasma gondii.
abstract: Apicomplexan parasites--including the causative agents of malaria (Plasmodium sp.) and toxoplasmosis (Toxoplasma gondii)--harbor a secondary endosymbiotic plastid, acquired by lateral genetic transfer from a eukaryotic alga. The apicoplast has attracted considerable attention, both as an evolutionary novelty and as a potential target for chemotherapy. We report a recombinant fusion (between a nuclear-encoded apicoplast protein, the green fluorescent protein and a rhoptry protein) that targets to the apicoplast but grossly alters its morphology, preventing organellar segregation during parasite division. Apicoplast-deficient parasites replicate normally in the first infectious cycle and can be isolated by fluorescence-activated cell sorting, but die in the subsequent host cell, confirming the 'delayed death' phenotype previously described pharmacologically, and validating the apicoplast as essential for parasite viability.
authors.affiliation: Department of Biology, 305 Goddard Laboratories, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: C Y
authors.initials: CY
authors.lastname: He
authors.forename: M K
authors.initials: MK
authors.lastname: Shaw
authors.forename: C H
authors.initials: CH
authors.lastname: Pletcher
authors.forename: B
authors.initials: B
authors.lastname: Striepen
authors.forename: L G
authors.initials: LG
authors.lastname: Tilney
authors.forename: D S
authors.initials: DS
authors.lastname: Roos
mesh_terms: D000818:Animals; D056890:Eukaryota / Q000235:genetics; D017125:Genes, Protozoan; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics; D008854:Microscopy, Electron; D009154:Mutation; D010641:Phenotype; D018087:Plastids / Q000235:genetics*; D015800:Protozoan Proteins / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics; D013559:Symbiosis / Q000235:genetics; D014122:Toxoplasma / Q000235:genetics* / Q000254:growth & development / Q000382:microbiology
chemical_list: D008164:Luminescent Proteins; D008565:Membrane Proteins; D015800:Protozoan Proteins; C117001:ROP 1 protein, Toxoplasma gondii; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins