In vitro production of cat-restricted Toxoplasma pre-sexual stages by epigenetic reprogramming

Sexual reproduction of Toxoplasma gondii, which is restricted to the small intestine of felids, is sparsely documented in studies involving domestic cats, which also raises ethical concerns. Chromatin modifiers dictate the developmental fate of the parasite during its multistage life cycle, but their targeting to stage-specific cistromes is poorly described. Here we show that AP2XII-1 and AP2XI-2, two transcription factors expressed in tachyzoites, a stage that causes acute toxoplasmosis, silence genes specific to merozoites, a developmental stage critical for sexual commitment and transmission to the next host, including humans. Their conditional and simultaneous depletion leads to a drastic change in the transcriptional program, promoting a complete transition from tachyzoites to merozoites, as revealed by mass spectrometry-based proteomic analyses of the parasites.