Genetic Characterization of Plasmodium Putative Pantothenate Kinase Genes Reveals Their Essential Role in Malaria Parasite Transmission to the Mosquito.

Robert J Hart,Emily Molina,Amanah Abraham,Catherine S Nation,Choukri Ben Mamoun,Emmanuel Cornillot,Ahmed S I Aly

doi:10.1038/srep33518

Abstract

The metabolic machinery for the biosynthesis of Coenzyme A (CoA) from exogenous pantothenic acid (Vitamin B5) has long been considered as an excellent target for the development of selective antimicrobials. Earlier studies in the human malaria parasite Plasmodium falciparum have shown that pantothenate analogs interfere with pantothenate phosphorylation and block asexual blood stage development. Although two eukaryotic-type putative pantothenate kinase genes (PanK1 and PanK2) have been identified in all malaria parasite species, their role in the development of Plasmodium life cycle stages remains unknown. Here we report on the genetic characterization of PanK1 and PanK2 in P. yoelii. We show that P. yoelii parasites lacking either PanK1 or PanK2 undergo normal asexual stages development and sexual stages differentiation, however they are severely deficient in ookinete, oocyst and sporozoite formation inside the mosquito vector. Quantitative transcriptional analyses in wild-type and knockout parasites demonstrate an important role for these genes in the regulation of expression of other CoA biosynthesis genes. Together, our data provide the first genetic evidence for the importance of the early steps of pantothenate utilization in the regulation of CoA biosynthesis and malaria parasite transmission to Anopheles mosquitoes.

Highlights

Earlier metabolic analyses[5,6,15] and more recent studies in P. falciparum have indicated that pantothenic acid uptake and utilization are absolutely crucial for asexual blood stage development of the parasite within human erythrocytes[7,8,9,10,16,17]
In order to determine whether PanK1 and PanK2 are expressed during P. yoelii asexual development in mouse erythrocytes, RT-PCR analyses were performed on total RNA isolated from erythrocytes infected with the wild-type (WT) 17XNL strain of P. yoelii
Our studies provide the first genetic evidence that the two candidate pantothenate kinase genes of P. yoelii are critical for malaria transmission to the mosquito but that loss of one or the other does not alter asexual development or sexual differentiation

Summary

Introduction

Earlier metabolic analyses[5,6,15] and more recent studies in P. falciparum have indicated that pantothenic acid uptake and utilization are absolutely crucial for asexual blood stage development of the parasite within human erythrocytes[7,8,9,10,16,17]. Consistent with these data, pantothenate analogs inhibit intraerythrocytic development of P. falciparum[16,18,19]. These knockout parasites are severely deficient in ookinete development and completely blocked in their ability to produce sporozoites in Anopheles mosquitoes

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Conclusion