DiCre approach. "Parasite counts by fluorescence-activated cell sorting (FACS) revealed that induced-KO of pfap2 prevented parasite replication within a single asexual cycle, without appreciable recovery over multiple cycles (Fig. 2D), showing that pfap2 is required for asexual replication in vitro. Importantly, the Cre-mediated endogenous pfap2 KO was fully complemented with an episomally expressed copy of AP-2 -GFP under a constitutive promoter." "When examined by Giemsa staining, parasites lacking pfap2 arrest as malformed schizonts which are still present in the culture at 60 h postinvasion (Fig. 2H). These defective schizonts occupy approximately half of the red cell cytoplasm and contain poorly segmented merozoites compared to wild-type schizonts. Consistent with reduced size, pfap2 KO schizonts carried fewer nuclei (mean standard deviation [KO, 13.0 4.9; wild type, 19.3 4.8; P  0.0001; n  50 KO and 50 wild type]). As determined by FACS, the mean DNA content may be slightly lower in KO schizonts (mean standard deviation [KO, 18,180 8,900 U; wild type, 19,980 10,000 U; P  0.001; n  21,924 events [KO] and 21,552 events [wild type]), but this difference is small and does not explain the more than 45% difference in number of segmented nuclei (Fig. S6). Rarely, rap-treated parasites were observed to undergo egress and invasion, probably due to occasional failure to excise pfap2 ." Widespread defects in merozoite morphology.