Genetic deletion of the Toxoplasma heme biosynthetic genes.
a, Schematic illustration of a general CRISPR-Cas9-based strategy for gene deletion in Toxoplasma. b, PCR confirmation of gene ablation. The genomic locations of the primers used in PCR amplification were indicated in the scheme. c, The loss of messenger RNA of the genes of interest was confirmed by reverse-transcription PCR (RT-PCR). d, The correct integration of the drug resistance cassette into the TgFECH locus during gene deletion was detected by PCR. However, the knockout parasites cannot be cloned probably due to its non-viability. GOI, gene of interest; DRC, drug resistance cassette.