Fig. 1: CS1 is required for parasite growth.

a CRISPR/Cas9-assisted 3’-genomic tagging of the CS1 gene with a spaghetti monster HA (smHA) tag in the RHΔku80 strain. HSP60 (magenta) was used as a mitochondrial marker. Scale bars, 5 μm. b A 7-day plaque assay to evaluate the growth of DiCre (RH DiCre_T2A Δku80Δhxgprt) and Δcs1 mutant (100 tachyzoites/well, 3 wells/strain). c The relative size of plaques from (b) (means ± SEM; ****p ≤ 0.0001, Student’s t test). d Replication efficiency of DiCre and Δcs1 strains. The number of vacuoles was counted 24 hours post-invasion (n = 4 independent experiments, means ± SEM; two-way ANOVA). e Virulence test of ICR mice infected with DiCre or Δcs1 stains (10² or 10⁴ parasites/mouse and 6–8 mice/group). f Parasite burden in the peritoneal fluid of mice. ICR mice were infected with DiCre or Δcs1 mutants (10⁴ tachyzoites/mouse and 5 mice/strain). Parasite load in peritoneal fluid was calculated 5 days post-infection by qPCR based on the non-coding fragment length of 529 bp.