The transcription factor AP2XI-2 is a key negative regulator of Toxoplasma gondii merogony
Commitment to and completion of sexual development are essential for Toxoplasma gondii to produce oocysts in the intestine of the feline host. Understanding of the molecular mechanism responsible for sexual commitment is extremely limited due to the lack of model systems. Here, we show that the transcription factors AP2XI-2 and AP2XII-1 associated with the epigenetic repressors MORC/HDAC3 complex 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 merozoites, but they play different roles in the merogony process. Depletion of AP2XI-2 in type II Pru strain induced parasites to undergo merogony and produce mature merozoites in alkaline medium but not in neutral medium, whereas the AP2XII-1 depleted Pru strain underwent several rounds of schizogony and produced merozoites in neutral medium and more markedly under alkaline conditions. Furthermore, we show that two AP2XI-2 interacting proteins are also involved in repressing merozoite programming. Overall, these findings indicate that the merozoite primed pre-sexual commitment is controlled by an intricate regulatory network and that AP2XI-2 or AP2XII-1 depleted parasites can be used as a model to study the merogony in vitro. Overall design: We report genome-wide AP2XI-2 and AP2XII-1 profiles in Toxoplasma gondii using CUT&TAG