title: Tetracycline analogue-regulated transgene expression in Plasmodium falciparum blood stages using Toxoplasma gondii transactivators.
abstract: Genetic manipulation has revolutionized research in the Apicomplexan parasite Plasmodium falciparum, the most important causative agent of malaria. However, to date no techniques have been established that allow modifications that are deleterious to blood-stage growth, such as the disruption of essential genes or the expression of dominant-negative transgenes. The recent establishment of a screen for functional transactivators in the related parasite Toxoplasma gondii prompted us to identify transactivators in T. gondii and to examine their functionality in P. falciparum. Tetracycline-responsive minimal promoters were generated based on the characterized P. falciparum calmodulin promoter and used to assess transactivators in P. falciparum. We demonstrate that artificial tetracycline-regulated transactivators isolated in T. gondii are also functional in P. falciparum. By using the tetracycline analogue anhydrotetracycline, efficient, stage-specific gene regulation was achieved in P. falciparum. This regulatable expression technology has clear potential for the study of essential gene function in P. falciparum blood stages. On the other hand, the identified transactivators are not functional in mammalian cells, consistent with the fundamental differences in the mechanism of gene regulation between Apicomplexan parasites and their human hosts.
authors.affiliation: The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville VIC 3050, Australia.
authors.forename: Markus
authors.initials: M
authors.lastname: Meissner
authors.forename: Efrosinia
authors.initials: E
authors.lastname: Krejany
authors.forename: Paul R
authors.initials: PR
authors.lastname: Gilson
authors.forename: Tania F
authors.initials: TF
authors.lastname: de Koning-Ward
authors.forename: Dominique
authors.initials: D
authors.lastname: Soldati
authors.forename: Brendan S
authors.initials: BS
authors.lastname: Crabb
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004912:Erythrocytes / Q000469:parasitology*; D005786:Gene Expression Regulation / Q000187:drug effects*; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000235:genetics*; D013754:Tetracyclines / Q000494:pharmacology*; D014122:Toxoplasma / Q000235:genetics*; D015534:Trans-Activators / Q000502:physiology*; D019076:Transgenes
chemical_list: D013754:Tetracyclines; D015534:Trans-Activators