Putative transcription factors show cyclic RNA abundance patterns.

Cell cycle expression profiles were assessed for 68 predicted AP2 domain genes [49] and 9 genes containing C2H2 Zn-finger domains (TGME49_103050, _121330, _101340, _086710, _006650, _002470, _059650, _023570, _111450) found in the Toxoplasma genome. (A) Maximum expression of RNA polymerases was tightly clustered in the G1-subtranscriptome along with a few general transcription factors. By contrast, the times of peak expression for 24 AP2 (see full list Table S1) and four activator Zn-finger domain genes were distributed across the tachyzoite division cycle (Table S2). In comparison, mRNAs encoding RNA polymerases showed peak expression clustered in G1. Relatively few general transcription factors and less than a third of known chromatin remodelers [87] also have cyclical patterns (see also Table S2). (B) Spline model curves for selected cell cycle AP2 mRNAs demonstrate relative abundance and time shifts indicating that the expression of these factors follows a serial order with peaks at different cell cycle stages.