Successful modification | The parasite was generated by the genetic modification |
The mutant contains the following genetic modification(s) |
Gene disruption,
Introduction of a transgene
|
Reference (PubMed-PMID number) |
Reference 1 (PMID number) : 28027318 |
MR4 number |
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Parent parasite used to introduce the genetic modification |
Rodent Malaria Parasite | P. berghei |
Parent strain/line | P. berghei ANKA |
Name parent line/clone |
P. berghei ANKA 507cl1 (RMgm-7)
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Other information parent line | P.berghei ANKA 507cl1 (RMgm-7) is a reference ANKA mutant line which expresses GFP under control of a constitutive promoter. This reference line does not contain a drug-selectable marker (PubMed: PMID: 16242190). |
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The mutant parasite was generated by |
Name PI/Researcher | Srivastava A, Waters AP |
Name Group/Department | Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation |
Name Institute | College of Medical, Veterinary and Life Sciences, University of Glasgow |
City | Glasgow |
Country | UK |
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Name of the mutant parasite |
RMgm number | RMgm-4074 |
Principal name | gdh1- |
Alternative name | |
Standardized name | |
Is the mutant parasite cloned after genetic modification | Yes |
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Phenotype |
Asexual blood stage | Not different from wild type |
Gametocyte/Gamete | Not different from wild type |
Fertilization and ookinete | Not different from wild type |
Oocyst | Reduced oocyst production |
Sporozoite | Reduced oocyst production |
Liver stage | Not different from wild type |
Additional remarks phenotype | Mutant/mutation
The mutant lacks expression of GDH1
Protein (function)
Glucose consumption by Plasmodium-infected RBC increases 10-fold and these stages rely primarily on glycolysis for energy generation. Notwithstanding their dependence on glycolysis, asexual blood stages maintain a single, poorly cristate mitochondrion and are dependent on electron transport chain (ETC) activity for the re-oxidation of inner membrane dehydrogenases and pyrimidine biosynthesis. The maintenance of the mitochondrial ETC is sustained in part, by the oxidation of pyruvate (diverted from glycolysis) and the uptake and catabolism of glutamine. Pyruvate can enter the TCA cycle via two pathways; through anaplerotic reactions involving the CO2-fixing enzyme, phosphoenolpyruvate carboxylase (PEPC), or through the activity of a repurposed branched chain α-keto acid dehydrogenase (BCKDH) complex, which substitutes for the activity of the missing mitochondrial pyruvate dehydrogenase in Plasmodium and other apicomplexan parasites. Despite the essentiality of the mitochondrion, operation of the TCA cycle is not required for intra-erythrocytic growth of P.falciparum.
Plasmodium spp. lack key enzymes involved in gluconeogenesis and all developmental stages are predicted to be dependent on the uptake of sugars. However, in contrast to the asexual blood stages, there is increasing evidence that the mosquito-infective stages of Plasmodium exhibit an increased dependence on the TCA cycle and mitochondrial metabolism.
Specifically, Plasmodium gametocytes develop more complex tubular mitochondrial cristae suggestive of increased mitochondrial function. Metabolomic analyses have confirmed increased TCA metabolism in P.falciparum gametocytes and demonstrated that this is essential for gametocyte maturation. Recent genetic studies have also shown that the TCA cycle is essential for the development of P.falciparum mosquito stages, consistent with earlier work in P.bergheid emonstrating that the TCA cycle and the electron transport chain are required for ookinete development and oocyst formation.
In this study a combination of metabolomic and reverse genetic approaches was used to investigate the metabolic changes that occur in key mosquitostages of P.berghei and the potential impact of these changes on parasite infection in the mosquito. We find that these stages are highly sensitive to disruptions in multiple pathways in central carbon metabolism including the TCA cycle, the utilisation of glutamine as a carbon source, intermediary carbon metabolism and coenzyme A (CoA) synthesis.
Phenotype
Normal growth and development throughout the life cycle, but reduced oocyst production
Additional information
Other mutants |