advanced fluorescence imaging: fluorescence resonance energy transfer (FRET) and deconvolution modules to study host-parasite ineractions during toxoplasma gondii infection

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Toxoplasmosis is an infection due to Toxoplasma gondii, which is a unicellular parasite that can grow within any cells of any warm-blooded vertebrates and is a major global zoonotic pathogen. This parasite is not only an important pathogen with enormous sociocultural and economical impact in Canada (major source of food contamination in meat industry, water contamination, children contaminated in utero), but also a biological system with great potential and a model for several aspects of intracellular parasitism. Our goal is to understand how Toxoplasma stimulates and interferes with the immune response in its vertebrate hosts. Using a multidisciplinary approach of cell biology, genetics and immunology, we focus on the isolation of parasite and host factors that interact to ultimately influence the outcome of the infection. We use genetic approaches to generate parasites that are impaired and unable to behave normally in their host, and then locate the mutation responsible for the defect. This allows us to identify important parasite factors that are required for an infection. These molecules are then characterized: we study their properties, their localization in the parasite or in the host, and we determine potential interacting molecules. The study of "protein-protein interactions" involves techniques of molecular biology, biochemistry and microscopy. Observing these interactions in physiological conditions in live host cells requires the use of labeled proteins, and specific technologies of microscopy termed "deconvolution" and "Fluorescence Resonance Energy Transfer (FRET)"; these two modules (requested in the present proposal) are basically added to an existing imaging station. By characterizing the interaction of host and parasite proteins using such technologies, we can (i) gain knowledge on how the parasite manipulates the host, and how the host reacts; (ii) increase our chances for innovation not only for research on Toxoplasma and intracellular organisms, but also for numerous biology, biochemistry and immunology studies; (iii) train high quality students; (iv) develop new technologies and patentable products; (v) ultimately bring sociocultural and economical benefits to Canada and other countries.