Fig. 7.

TgINCENP2 is essential for parasite replication and dictates the correct targeting of TgArk1. a Plaque assays were carried out by infecting HFF monolayers with TATi1-Δku80 or Tgincenp2i for 7 days ± ATc. The HFF were stained with Giemsa. b Immunofluorescence assays of HA₃-TgArk1 in intracellular Tgincenp2i parasites grown without or in the presence of ATc for 24 h. Endogenous TgArk1 was detected using anti-HA antibodies. The parasite pellicle was visualized using anti-GAP45 antibodies. Nuclei were stained with DAPI. Scale bars represent 2 μm. c–e Ultrastructural analysis of TgINCENP2-depleted parasites. c Vacuole containing two tachyzoites and an aberrant parasite with a multi-lobed nucleus. The cellular architecture is lost and the plasma membrane is only partially associated with an inner membrane complex (IMC, white arrows). A few organelles are randomly dispersed in the cytosol. d Vacuole showing a residual body containing a nucleus that can be distinguished from a parasite by the absence of IMC. The four tachyzoites connected to the residual body have an IMC and contain mitochondria and apical organelles, but no nucleus can be seen on this section. e Vacuole containing aberrant endodyogeny profiles, with tachyzoites containing encapsulated successive apical complexes (Russian dolls, white asterisks) and large residual bodies containing multiple nucleus sections. f–g′ Mitosis either in control or in TgINCENP2-depleted parasites. f Control parasites (TATi1-Δku80 treated with ATc): wild-type mitosis. Nascent IMC of daughter cells are indicated with white stars. The bud on the left shows one centriole (white arrow) located at the tip of the centrocone (higher magnification shown in f′, with the kinetochores aligned underneath (black arrows); the spindle microtubules are still present in between kinetochores. The other bud should show the same structure in another section plane. g Mutant parasites. The apical complexes of two developing daughter cells are visible (white stars). The invaginated nuclear envelope delineates an intra-nuclear funnel extending between the centrioles (higher magnification in g′)