Core - Genetic Crosses with Toxoplasma Gondii

Pfefferkorn, Elmer R.

Abstract

Toxoplasmic encephalitis is a major opportunistic infection in AIDS patients. Many of these patients cannot tolerate prolonged administration of pyrimethamine-sulfadiazine. Thus new drugs are needed to treat to prevent this disease. The rational search for improved drug would profit from knowledge as to the mechanism of action of current and future candidate drugs. A useful clue as to mechanism of action can be obtained by studying drug-resistant mutants of Toxoplasma gondii. One way to take advantage of these mutants is to use genetic analysis to identify the gene that confers resistance. Now that is a formal genetic map of T. gondii based on RFLP markers has been established, it is possible to localize drug-resistance genes. This Core Facility will isolate drug-resistant mutants of the PLK strain of T. gondii with the aid of chemical mutagenesis. These mutants will be crossed with a CEP strains of T. gondii that has three unlinked drug-resistance markets. These crosses will be carried out in the definitive host, the cat. Oocysts from the cat feces will be purified and allowed to sporulate. The bradyzoites will be released from sporulated oocysts and grown as tachyzoites in cultured human fibroblasts. Recombinant parasites that inherited drug resistance markers from both parents will be cloned and characterized. The recombinant clones will be sent to Dr. John Boothroyd's laboratory or RFLP analysis.

Funding Agency

• Agency: National Institute of Health (NIH)
• Institute: National Institute of Allergy and Infectious Diseases (NIAID)
• Type: Research Project--Cooperative Agreements (U01)
• Project #: 5U01AI030230-05
• Application #: 3727293
• Support Year: 5
• Fiscal Year: 1995

Institution

• Name: Palo Alto Medical Foundation Research Institute
• DUNS #: 622276137
• City: Palo Alto
• State: CA
• Country: United States
• Zip Code: 94301

Publications

Saeij, J P J; Boyle, J P; Coller, S et al. (2006) Polymorphic secreted kinases are key virulence factors in toxoplasmosis. Science 314:1780-3

McFadden, D C; Tomavo, S; Berry, E A et al. (2000) Characterization of cytochrome b from Toxoplasma gondii and Q(o) domain mutations as a mechanism of atovaquone-resistance. Mol Biochem Parasitol 108:12-Jan

McFadden, D C; Boothroyd, J C (1999) Cytochrome b mutation identified in a decoquinate-resistant mutant of Toxoplasma gondii. J Eukaryot Microbiol 46:81S-82S

Liesenfeld, O; Kang, H; Park, D et al. (1999) TNF-alpha, nitric oxide and IFN-gamma are all critical for development of necrosis in the small intestine and early mortality in genetically susceptible mice infected perorally with Toxoplasma gondii. Parasite Immunol 21:365-76

Soldati, D; Lassen, A; Dubremetz, J F et al. (1998) Processing of Toxoplasma ROP1 protein in nascent rhoptries. Mol Biochem Parasitol 96:37-48

Boothroyd, J C; Hehl, A; Knoll, L J et al. (1998) The surface of Toxoplasma: more and less. Int J Parasitol 28:3-9

Black, M W; Boothroyd, J C (1998) Development of a stable episomal shuttle vector for Toxoplasma gondii. J Biol Chem 273:3972-9

Neyer, L E; Kang, H; Remington, J S et al. (1998) Mesenteric lymph node T cells but not splenic T cells maintain their proliferative response to concanavalin-A following peroral infection with Toxoplasma gondii. Parasite Immunol 20:573-81

Manger, I D; Hehl, A B; Boothroyd, J C (1998) The surface of Toxoplasma tachyzoites is dominated by a family of glycosylphosphatidylinositol-anchored antigens related to SAG1. Infect Immun 66:2237-44

Manger, I D; Hehl, A; Parmley, S et al. (1998) Expressed sequence tag analysis of the bradyzoite stage of Toxoplasma gondii: identification of developmentally regulated genes. Infect Immun 66:1632-7