A genome-scale vector resource enables high-throughput reverse genetic screening in a malaria parasite.
Bottom Line: We present a large-scale resource of barcoded vectors with long homology arms for effective modification of the Plasmodium berghei genome.To validate the utility of this resource, we rescreen the P. berghei kinome, using published kinome screens for comparison.We find that several protein kinases function redundantly in asexual blood stages and confirm the targetability of kinases cdpk1, gsk3, tkl3, and PBANKA_082960 by genotyping cloned mutants.
Affiliation: Wellcome Trust Sanger Institute, Hinxton Cambridge CB10 1SA, UK.Show MeSH
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Mentions: Schizonts cotransfected with a cocktail of 48 vectors and injected into mice (Figure 2) gave rise to drug resistant parasites 4 days later. This was indicative of an overall transfection efficiency of ∼10−4 and suggested that roughly 2,500 independent recombination events occurred in a transfection, enough to generate a complex mixture of mutants. Blood samples were subsequently collected exactly every 24 hr from day 4, gDNA was extracted, and vector-specific barcodes were amplified by a polymerase chain reaction (PCR) with a generic primer pair (see Figure S1A available online) and counted on a benchtop next-generation sequencer (Figure 2). In each of two replicate experiments, the same 22 barcodes from the vector pool were robustly detected and yielded nearly identical growth curves (Figure 3A). Southern hybridization of separated chromosomes showed evidence for vector integration events throughout the genome (Figure S1B). Long-range PCR products confirmed integration events for 17 of the 22 replicating barcodes (Figure S1C).
Affiliation: Wellcome Trust Sanger Institute, Hinxton Cambridge CB10 1SA, UK.