Mutant/mutation
The mutant expresses a C-terminal GFP-tagged version of AP2-R2.
In addition, the mutant contains a gene encoding Cas9 from Streptococcus pyogenes, introduced into the c/d-ssu-rrna gene. This Cas9 nuclease does not cleave double stranded DNA in the absence of sgRNA and is thus suitable for generating the parasite which express it constitutively. It does not contain a drug-selectable marker which has been removed by negative selection.

Protein (function)
In Plasmodium spp., sexual development is triggered by AP2-G. It is an AP2-family transcription factor that is expressed in a subpopulation of blood-stage parasites, with disruption of the gene resulting in complete loss of the parasite’s capability to produce gametocytes. The target genes of AP2-G includes a female-specific transcription factor gene, ap2-fg. AP2-FG activates most female-specific genes, and disruption of this gene results in the formation of abnormal female gametocytes. Ap2-o3 (ap2-fg2) and ap2r-2 are also a target gene of AP2-G.It has been reported that in both P. berghei and P. yoelii, disruption of ap2-o3 results in arrest of parasite development during ookinete development (and therefore the name ap2-o3. AP2-R2, on the other hand, is expressed in female gametocytes, and disruption of this gene impairs ookinete development.

Previously  two putative transcriptional regulator genes were identified, ap2r-1 and ap2r-2, as a target gene of AP2-G and AP2-FG. Of these, ap2r-1 functions as a transcriptional activator in zygotes and is renamed ap2-z, but the functional role of ap2r-2 remains unknown. AP2R-2 has an ACDC domain at its C-terminus, but no AP2 domain. It is expressed in females, and ap2r-2 knockout parasites [ap2r-2(-)] are not able to form banana-shaped ookinetes.