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bioRxiv · 10.1101/401570

A mutagenesis screen for essential plastid biogenesis genes in human malaria parasites

Tang, Y.·Meister, T. R.·Walczak, M.·Pulkoski-Gross, M.·Hari, S. B.·Sauer, R. T.·Amberg-Johnson, K.·Yeh, E.
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Abstract

Endosymbiosis has driven major molecular and cellular innovations. Plasmodium spp. parasites that cause malaria contain an essential, non-photosynthetic plastid, the apicoplast, which originated from a secondary (eukaryote-eukaryote) endosymbiosis. To discover organellar pathways with evolutionary and biomedical significance, we performed a mutagenesis screen for essential genes required for apicoplast biogenesis in P. falciparum. Apicoplast-minus mutants were isolated using a chemical rescue that permits conditional disruption of the apicoplast and a new fluorescent reporter for organelle loss. Five candidate genes were validated (out of 12 identified), including a TIM-barrel protein that likely derived from a core metabolic enzyme but evolved a new activity. Our results demonstrate the first forward genetic screen to assign essential cellular functions to unannotated P. falciparum genes. A putative TIM-barrel enzyme and other newly-identified apicoplast biogenesis proteins open opportunities to discover new mechanisms of organelle biogenesis, molecular evolution underlying eukaryotic diversity, and drug targets against multiple parasitic diseases.

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Tang, Y., Meister, T. R., Walczak, M., Pulkoski-Gross, M., Hari, S. B., Sauer, R. T., Amberg-Johnson, K., Yeh, E.. 2018-08-27. A mutagenesis screen for essential plastid biogenesis genes in human malaria parasites. https://doi.org/10.1101/401570

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