Journal Article

Uncovering the essential genes of the human malaria parasite Plasmodium falciparum by saturation mutagenesis

Adapa, Swamy R., Jiang, Rays H. Y., Zhang, Min, Oberstaller, Jenna, Casandra, Deborah, Bronner, Iraad F., Rayner, Julian C., Li, Suzanne, Wang, Chengqi, Otto, Thomas D., Udenze, Kenneth, Adams, John H., Mayho, Matthew, Swanson, Justin, Liao, Xiangyun, Brown, Jacqueline

2018

Overview

Malaria is caused by eukaryotic Plasmodium spp. parasites that classically infect red blood cells. These are difficult organisms to investigate genetically because of their AT-rich genomes. Zhang et al. have exploited this peculiarity by using piggyBac transposon insertion sites to achieve saturation-level mutagenesis for identifying and ranking essential genes and drug targets (see the Perspective by White and Rathod). Genes that are current candidates for drug targets were identified as essential, in contrast to many vaccine target genes. Notably, the proteasome degradation pathway was confirmed as a target for developing therapeutic interventions because of the several essential genes involved and the link to the mechanism of action of the current frontline drug, artemisinin. Science , this issue p. eaap7847 ; see also p. 490 Mutagenesis of a human malaria parasite reveals a core set of genes essential for asexual growth in red blood cells in vitro. Severe malaria is caused by the apicomplexan parasite Plasmodium falciparum. Despite decades of research, the distinct biology of these parasites has made it challenging to establish high-throughput genetic approaches to identify and prioritize therapeutic targets. Using transposon mutagenesis of P. falciparum in an approach that exploited its AT-rich genome, we generated more than 38,000 mutants, saturating the genome and defining mutability and fitness costs for over 87% of genes. Of 5399 genes, our study defined 2680 genes as essential for optimal growth of asexual blood stages in vitro. These essential genes are associated with drug resistance, represent leading vaccine candidates, and include approximately 1000 Plasmodium -conserved genes of unknown function. We validated this approach by testing proteasome pathways for individual mutants associated with artemisinin sensitivity.

• Publisher: The American Association for the Advancement of Science
• Subject: Animals / Antimalarials - pharmacology / Artemisinins - pharmacology / Coding / Conserved Sequence / Degradation / Disruption / Drug resistance / Drug Resistance - genetics / Erythrocytes / Erythrocytes - parasitology / Fitness / Gene sequencing / Genes / Genes, Essential / Genes, Protozoan / Genetic Fitness / Genetics / Genomes / Homology / Humans / Insertion / Lipids / Malaria / Malaria Vaccines - genetics / Malaria, Falciparum - parasitology / Mathematical analysis / Mode of action / Mutagenesis / Mutants / Parasites / Parasitic diseases / Phenotypes / Phosphorylation / Plasmodium / Plasmodium falciparum / Plasmodium falciparum - drug effects / Plasmodium falciparum - genetics / Plasmodium falciparum - growth & development / Proteasomes / Ranking / Reproduction, Asexual - genetics / Saturation / Target recognition / Therapeutic applications / Vaccines / Vector-borne diseases / Virulence