Fig. 1.

Introduction of silent attB element to enable gene editing. a Sequences of attB and attP used in P. falciparum transfections. Integrase-mediated recombination yields attL and attR elements as shown. The conserved 8 bp core sequence is shown in red; a non-palindromic 5’-GT dinucleotide (grey highlight) prevents self-ligation after cleavage by Bxb1 integrase and promotes efficient strand exchange. b Strategy for introducing attB into the intron of a gene of interest (GOI). The pCC1-attB plasmid carries an upstream sequence (light blue) to facilitate homologous recombination into the parasite genome, an intron with an inserted attB, and a recodonized version of the remainder of the gene (red). The hdhfr cassette permits selection of successfully transfected parasites. Recombination of the plasmid into the parasite genome yields the required attB-carrying parasite without affecting target gene transcription or associated phenotypes