Mutant/mutation
The mutant expresses a GFP-tagged (C-terminal) version of AP2-Sp (transcription factor with AP2 domains).

Protein (function)
AP2-Sp belongs to the Apetala2 (AP2) family of genes which encode transcription factors (TFs). The AP2 family TFs were first identified in plants. Plant AP2 family TFs are named for their possession of at least one common DNA-binding domain of approximately 60 amino acids, the AP2 domain. Bioinformatic analyses have revealed the presence of 26 AP2-related genes in the Plasmodium genome. The predicted Plasmodium AP2-related genes encode proteins with one to four AP2 domains. AP2-Sp contains a single AP2 domain. See also mutant RMgm-399 lacking expression of AP2-Sp. Phenotype analyses of this mutant indicate an essential role of AP2-Sp for sporozoite formation and indicate that  AP2-Sp is a transcription factor that binds to promoter regions of genes that are expressed during sporozoite development and activates expression of genes, including genes involved in sporozoite infectivity.

Phenotype
GFP fluorescence was observed in some oocysts 6 days after the infective blood meal The proportion of GFP-positive oocysts increased with time. In these oocysts signals were weak and localized in Hoechst-stained spotted nuclei of the sporoblasts. In day 10 oocysts (new) strong GFP signals appeared in oocysts. These signals were localized to the nuclei of sporozoites budding from sporoblasts and displayed ringlike appearances around the core of the sporoblasts. GFP-expression in both oocyst-derived and salivary gland sporozoites. Fluorescence signals were localized to the nuclei of sporozoites.

Additional information
Evidence has been presented that the P. falciparum ortholog (PF14_0633) of P. berghei AP2-Sp is (also) transcribed in asexual blood stages (de Silva et al., PNAS, 2008, 105, 8393-8; Bozdech Z et al., 2003, PloS Biol. 1: E5).

Phenotype analyses of a P. berghei mutant lacking expression of AP2-Sp (RMgm-399) indicate an essential role of AP2-Sp for sporozoite formation and indicate that  AP2-Sp is a transcription factor that binds to promoter regions of genes that are expressed during sporozoite development and activates expression of genes, including genes involved in sporozoite infectivity.

A transgenic parasite mutant was generated (RMgm-400) that express endogenous AP2-O (APETALA2 in ookinetes; PBANKA_090590; PF11_0442), but whose AP2 domain had been swapped with that of AP2-Sp. It is shown that in this mutant expression of several target genes of AP2-Sp were induced in the ookinete stage.

Other mutants
RMgm-399: a mutant lacking expression of AP2-Sp (AP2 in sporozoites)
RMgm-400: a mutant expressing a mutated form of AP2-O (PBANKA_090590; PF11_0442)whose AP2 domain had been swapped with that of AP2-Sp
RMgm-207: a mutant lacking expression of AP2-O (AP2 in ookinetes: PBANKA_090590; PF11_0442)
RMgm-208: a mutant expressing a GFP-tagged form of AP2-O (AP2 in ookinetes; PBANKA_090590; PF11_0442)