Fig. 8: ME is critical for the lytic cycle of tachyzoites.

a Immunofluorescent microscopic analysis of ME. Hoechst is a cell nucleus marker. b Immunofluorescence detection of co-localization of native ME with the nucleus marker, Hoechst. c Immunofluorescent localization and regulation of ME by indole-3-acetic acid (IAA). Intracellular miniAID-ME tachyzoites cultured in the absence or presence of 500 μM IAA were stained by α-HA and α-ALD antibodies. d The growth of TiR1 (RHΔku80-TiR1) and miniAID-ME tachyzoites was compared by plaque assay (−/+500 μM IAA, 7d, 100 tachyzoites/well and 3 wells for each strain). e Intracellular growth of TiR1 and miniAID-ME strains (−/+500 μM IAA, 24 h, means ± SEM, n = 3 independent experiments. ****p ≤ 0.0001, two-way ANOVA). f ICR mice were infected with TiR1 and miniAID-ME tachyzoites by intraperitoneal injection (10⁴ tachyzoites/mouse and 5 mice/strain). IAA was added to the drinking water or not. After 5 days of infection, parasite loads in peritoneal fluids were calculated by qPCR based on the 529 gene, ****p ≤ 0.0001, Student’s t test. g, h Immunostaining and quantification of histone acetylation in the parasite nucleus. Analyses were performed using rabbit anti-H3K9ac antibody, and the fluorescence intensity was quantified. Each symbol in panel (h) marks the pixel density of a parasite nucleus (means ± SEM, n = 3 assays. ****p ≤ 0.0001, Student’s t test).