Protein expression and localization of PfCRISP in sexual stages. (A) Bacterially expressed recombinant 6×His tagged PfCRISP electrophoresed on SDS-PAGE gel revealed that PfCRISP exists as a monomer which runs around ~ 27 kDa and an oligomer around ~75 kDa. (B) IFAs were performed on WT NF54 asexual blood stages (ring, trophozoite, schizont) to localize PfCRISP (green) in combination with PfCDPK4 (red) in solution in microcentrifuge tubes. The parasite nucleus was localized with 4′ ,6-diamidino-2-phenylindole (DAPI) (in blue). Scale bar = 5 μm. (C) IFAs were performed on gametocytes in solution in microcentrifuge tubes using anti-PfCRISP antisera (in green) in combination with PfCDPK4 (in red). IFAs were performed on gametocytes 10 min post activation and free microgametes on thin smears using anti-PfCRISP antisera (in green) in combination with PfCDPK4 (in red). The parasite nucleus was stained with DAPI (blue). White arrow marks one end of the microgamete. Scale bar = 5 μm. (D) IFAs were performed on gametocytes on thin smears using anti-PfCRISP antisera (in green) in combination with Pfg377 (in red). The parasite nucleus was stained with DAPI (blue). Scale bar = 5 μm.

Kumar S, Leeb AS, Vaughan AM, Kappe SHI. Plasmodium falciparum Cysteine Rich Secretory Protein uniquely localizes to one end of male gametes. Mol Biochem Parasitol. 2022 248:111447.