Fig. 8

Alteration of Pyheul gene transcript level decreases host mortality. a Diagrams showing plasmid construct and strategy to insert a drug-resistant cassette into the 5′ untraslated region (5′ UTR) of the putative HECT E3 ubiquitin ligase (PyHEUL) gene. Tg_dhfr, Toxoplasma gondii dihydrofolate reductase; gfp, green fluoresecent protein gene. b, c, d PCR products amplified from genetically modfied clones using primers as indicated in (a). e Dynamics of the mean parasitenia of N67 and two mutants with insertion of a plasmid at 5′UTR of the Pyheul gene. SDs are from three to five infected mice each. f Mortality rates of mice infected with N67 and the two mutant clones. g Pyheul mRNA transcript levels of N67 and YM parasites, normalized to those of 18 S rRNA. The level of YM was treated as 1. h Pyheul mRNA transcript levels expressed as fold changes (compared to that of N67) in the mutant clones. The transcript levels were calculated results of RT-qPCR using primers specific for the PyHECT E3 ligase and normalization of expression levels to those of parasite 18 s rRNA. For (g, h), at least three indepepndent repeats. Two-sided t-test, *P < 0.05; **P < 0.01