RNA-seq of AP2XI-2 or AP2XII-1 depleted Toxoplasma gondii

Commitment to and completion of sexual development are essential for Toxoplasma gondii to be transmitted through the oocysts. The molecular mechanism responsible for sexual commitment is extremely limited due to due to a lack of model systems. Here, we show that the transcription factors AP2XI-2 and AP2XII-1 associated with the epigenetic repressors MORC/HDAC3 complex, an upstream transcriptional repressor of sexual commitment, are constitutively expressed in both tachyzoite and bradyzoite stages but not in the merozoite stage. Depletion of AP2XI-2 or AP2XII-1 elicits the expression of genes specific to the merozoite but they have different roles in the merogony process. Depletion of AP2XI-2 in the type II Pru strain can induce parasites undergoing merogony to produce mature merozoites under alkaline media but not in the normal media, whereas the AP2XII-1 depleted can undergo several rounds of schizogonic replication to produce merozoites in both normal and alkaline media with a more pronounced extent under alkaline media. Furthermore, we showed that two other AP2XI-2 interacting proteins also involved in repress the merozoite program. Overall, these findings indicate that the merozoite primed pre-sexual commitment is involved in an intricate regulatory network and the AP2XII-2 or AP2XII-1 depleted parasites can be used as a model to study the merogony in vitro.