Morphogenesis of the centrosome during the tachyzoite cell cycle.

<p>(A) Morphological transitions of the outer and inner protein core complexes were monitored in the dual epitope-tagged TgSas-6^HA/TgCEP250-L1^myc clone. Co-staining with antibodies against TgMORN1 was used to visualize the nuclear membrane centrocone compartment (spindle pole). Above the fluorescent merged images (Merge) a diagram of the composite structures is placed within the cell cycle timing of the biosynthetic events. Five distinctive morphological transitions were identified, and three sequential duplication events (white arrows) were recorded in the following order: duplication of the outer core (TgSas-6^HA, blue panel) followed by the inner core (TgCEP250-L1^myc, red panel) and lastly, the centrocone (anti-TgMORN1 antibody, green panel). The cell cycle stages for each transition of the centrosome cycle were determined using well-established nuclear and cellular morphologies. (B) Super resolution images of the centrosome cores (TgSas-6^HA/TgCEP250-L1^myc) in relation to the centromeres (visualized with anti-TgCenH3 antibody) in the tachyzoite metaphase and anaphase/telophase. The diagram to the right of each image estimates the physical position and distance between the middle points of the three mitotic structures: outer and inner centrosome cores and kinetochore.