| Toxoplasma gondii and other members of the phylum Apicomplexa divide by assembling daughters within the mother on a scaffold consisting of cytoskeletal elements and flattened membrane vesicles. Maternal cytoplasm and organelles are then partitioned between these compartments. In T. gondii, two daughters are normally formed in each cell cycle (endodyogeny), while other apicomplexan species (such as Plasmodium sp., the causative agents of malaria) execute multiple cycles of DNA replication before packaging multiple daughter cells simultaneously (schizogony and endopolyogeny). This thesis investigates how T. gondii coordinates various cell cycle events, including scaffold formation, DNA replication, organelle replication and partitioning and establishes that T. gondii is capable of carrying out any one of the above replication patterns: endodyogeny, schizogony and endopolyogeny. In parallel with studying the dynamics of cell division, this thesis also explores the molecular nature of the parasite scaffold components, identifying a novel tubulin polymer within the conoid, a motile organelle at the apical end of the parasite, thought to be essential for host cell invasion. |
