RPS19 and cyst: When we assessed DBA staining in all HA+ vacuoles in this transfected population we found that 63% of the HA+, TgPRUΔROCY1 vacuoles formed DBA-positive cysts, while not a single parasite vacuole (out of 105) expressing the CCCH mutant form of NHA-ROCY1 was identified as a DBA-positive cyst (Fig. 4b; ChiSquared P < 0.0001).