The highly efficient endodyogeny of tachyzoites is a key process driving acute infection by Toxoplasma gondii. The centrocone is a specialized and critical structure for parasite cell division, but the regulatory mechanisms of centrocone proteins in T. gondii remain poorly understood. In this study, we characterized the centrocone protein SMCN1, which exhibited periodic expression in tachyzoites, peaking during the synthesis phase. Conditional depletion of SMCN1 was achieved in the type I RH strain and type II cyst-forming PRU strain using the mAID system combined with CRISPR-Cas9. Depletion of SMCN1 disrupted IMC assembly, endodyogeny and nuclear division, as well as the stable inheritance of the apicoplast and centrosome, resulting in severe defects in intracellular replication and impaired tachyzoite growth. Collectively, these results indicate that SMCN1 regulates cell division by coordinating organelle inheritance and cytoskeletal dynamics, ensuring proper replication of T. gondii tachyzoites and provide insights into mechanisms controlling parasite proliferation.
Li et al. (Wed,) studied this question.