A tetracycline-responsive transcription system (Tet-Off) adapted for use in Toxoplasma gondii (nicknamed TATi) is useful for molecular biological studies of this organism. Previous studies using TATi incorporated minimal promoters derived from the gene promoters for TgSAG1 or TgSAG4. The present study achieves improved activation and suppression of an integrated reporter gene in the absence and presence of anhydrotetracycline, respectively (p < 0.0001), by use of a newly derived minimal promoter based on the core promoter of TgGRA2. In comparison with the SAG1 minimal promoter, use of the GRA2 minimal promoter in stable transfectants has a 23-fold higher Signal to Noise Ratio for EYFP fluorescence in the absence or presence of anhydrotetracycline. We conclude that the performance of TATi for both activation and suppression of transcription can be markedly enhanced by incorporating a GRA2 minimal promoter.

适用于弓形虫（昵称 TATi）的四环素响应转录系统 (Tet-Off)可用于该生物的分子生物学研究。以前使用 TATi 的研究纳入了源自TgSAG1或TgSAG4基因启动子的最小启动子。本研究通过使用基于TgGRA2核心启动子的新衍生最小启动子，分别在无水四环素存在和不存在的情况下实现了整合报告基因的改进激活和抑制（p < 0.0001）。与SAG1最小启动子相比，使用GRA2在无水四环素存在或不存在的情况下，稳定转染子中的最小启动子对于 EYFP 荧光的信噪比高 23 倍。我们得出的结论是，通过掺入GRA2最小启动子，可以显着增强TATi在转录激活和抑制方面的性能。