ApiAP2 are a family of conserved transcription factors (TF) that play an important role in regulating gene expression in apicomplexan parasites. ApiAP2 proteins that may control the cell cycle dependent expression program are to be discovered. To better understand how these cell-cycle dependent gene expression profiles are established, we identified ApiAP2 proteins showing a cell cycle dependent expression. Using the Auxin-degradation system, we produced several inducible knock-down (iKD) mutant for these ApiAP2 proteins. Among them, a cell-cycle regulated ApiAP2 is expressed during the late S-phase of the tachyzoite cell-cycle. The iKD mutant parasites for this gene are unable to proliferate. In presence of Auxin, the mutant parasites do not produce daughter cells and are arrested in the early phase of budding. This indicates that this TF may specifically regulate the early steps of the daughter cell formation. Using RNA-Seq, we demonstrate that the level of expression of number of transcripts is affected by the knock-down of this potential TF. Overall design: Three biological replicate of the mutant strain in presence and in abscence of Auxin. mRNA profiles iKD TgAP2IX-5 parasites was generated by high throughput sequencing using HiSeq 2500 system (Illumina).