Organellar dynamics during the cell cycle of Toxoplasma gondii

摘要: The protozoan phylum Apicomplexa encompasses approximately 5000 species of obligate intracellular parasites, including those responsible for malaria and toxoplasmosis. Rather than dividing by binary fission, apicomplexans use a remarkable mechanism replication, assembling daughters de novo within the cytoplasm. Here, we exploit time-lapse microscopy fluorescent markers targeted to various subcellular structures in Toxoplasma gondii tachyzoites determine how these unicellular eukaryotes efficiently package complete set organelles, maintaining highly polarized organization necessary host cell invasion pathogenesis. Golgi division elongation apicoplast are among first morphologically observable events, associated with an unusual pattern centriolar migration. Daughter parasites assembled on cytoskeletal scaffolding, whose growth proceeds from apical end, encapsulating divided Golgi. Further extension scaffold results partitioning apicoplast, nucleus, endoplasmic reticulum, finally mitochondrion, which enters developing rapidly, but only very late during cycle. specialized secretory organelles (micronemes rhoptries) form novo. This distinctive replication -- organellar segregation spans 75% cycle, completely encompassing S phase suggests cycle regulation.