Fig. 1.

MyoA- but not MyoC-deficient tachyzoites enter non-phagocytic host cells with a significantly slower kinetics than MyoA⁺ tachyzoites. a lox-MyoA and ΔMyoA tachyzoites organized under typical rosettes inside U2OS cells after 24–40 h of intracellular growth. After fixation cells are processed for triple immunofluorescence: parasites are stained for the Ty epitope tag that is expressed in fusion with MyoA which is encoded by a loxP-flanked MyoA copy and for the Toxoplasma rhoptry protein toxofilin while the host cell F-actin cytoskeleton is visualized with fluorescent phalloidin. Maximal z projection from image stacks confirms that the ΔMyoA strain is specifically negative for Ty fluorescence. Scale bars: 5 μm. b Comparative kinetic analysis of host cell entry by lox-MyoA (n = 235), ΔMyoA (n = 300), and ΔMyoC (n = 200) tachyzoites. Entry duration is evaluated based on the first and last frames in which the zoite displays a clear body constriction that signs for the TJ. Statistics are performed with the Fisher test, P value is shown. NS not significant