Fig. 3

Lack of TgANT decreased the growth of parasites. a Schematic of CRISPR/Cas9 strategy used for gene deletion. b PCR analysis confirmed knockout of the ant gene in the gene deletion mutant (Δant). c Plaque assays were used to compare the overall growth ability of the RHΔku80, Δant and iΔant strains. Each well was infected with 150 parasites, and plaques were stained after 7 days. d Plaque areas were measured by counting pixel points in Photoshop C6S software (Adobe Inc.). The data are compiled from three independent experiments. The plaque assay showed that Δant strains had distinct growth defects. Asterisks indicate significant differences at *P < 0.05 and ****P < 0.0001. e Parasite invasion into HFFs was examined. The invasion rate of the Δant strain was 51%, which was significantly different from that of the RHΔku80 strain (62%). Data are presented as the mean ± standard deviation of the results from three assays. Asterisks indicate significant differences at*P < 0.05 and ***P < 0.001. f Comparison of intracellular replication ability of Δant, iΔant, and RHΔku80 strains. In the Δant strain, the proportions of PVs containing 1, 2 and 4 parasites was 35, 49 and 51%, respectively, and it was almost impossible to observe PVs containing > 4 parasites. The proportions of PVs containing 1, 2, 4, 8 and 16 parasites in the RHΔku80 strain was 0, 1%, 34, 35 and 15%, respectively. HFFs, Human foreskin fibroblasts; PVs, parasitophorous vacuoles; Δ, gene knockout; iΔ, gene complement