AP2Ⅺ-3 is critical for the cell cycle of Toxoplasma to progress through the G1 phase

This parasite has a complex life cycle that is well controlled to achieve optimal transmission and pathogenesis. Acute phase of the disease is caused by rapid proliferation of tachyzoites, which has a highly coordinated and tightly regulated cell cycle to allow parasite propagation.

Tachyzoite cell cycle has five partially overlapping phases (G1, S, G2, M and C) with distinct gene expression patterns and cellular activities, yet the underlying regulatory mechanisms are not well understood. In this study, we show that the AP2 family transcription factor AP2Ⅺ-3 has important roles in regulating the cell cycle to progress through the G1 phase. Depletion of AP2Ⅺ-3 resulted in cell cycle retention at G1 and impaired parasite division, leading to growth inhibition of tachyzoites.