Fig. 1

Generation of a P. falciparum mutant expressing a genomically encoded VAR2CSA-mEOS2 fusion protein. a The transfection strategy, using CRISPR/Cas9 genome editing technology, is outlined to insert two copies of the mEOS2 coding sequence between the regions encoding the NTS and the DBL1x domain of var2csa. The domain structure of the resulting VAR2CSA^mEOS2 is shown. The positions of relevant primers for analysis are indicated. b The integration event was verified by PCR, using genomic DNA or total mRNA from the resulting mutant, termed G6, and the parental FCR3 strain. The primer pairs used are indicated. Where indicated, RT-PCR was performed in the presence and absence of reverse transcriptase (RT). A size marker is indicated in kilo base pairs (kb). c Representative confocal immuno-florescence image of a live HbAA erythrocyte infected with G6 stained with the Zenon-labeled monoclonal antibody PAM 8.1 that is specific to the DBL3-X domain of VAR2CSA²⁴. A mid-sectional plane is shown. Bar, 2 µm. d A representative immuno-electron micrograph of G6 showing labelling of knobs with the anti-VAR2CSA monoclonal antibody followed by a goat anti human antibody coupled to 10 nm protein A gold. Bar, 100 nm