Additional remarks phenotype | Mutant/mutation
The mutant lacks expression of PBGD (published in bioRxiv preprint doi: https://doi.org/10.1101/589242. This version posted June 13, 2020).
Protein (function)
The malaria parasite is capable of de novo heme biosynthesis despite its ability to acquire heme from red blood cell (RBC) hemoglobin. The first enzyme of the de novo heme-biosynthetic pathway, δ-aminolevulinate synthase (ALAS) and the last two enzymes, Protoporphyrinogen IX oxidase (PPO) and Ferrochelatase (FC) localize to the mitochondrion. The enzymes that catalyze the intermediate steps: ALA dehydratase (ALAD), Porphobilinogen deaminase (PBGD) and Uroporphyrinogen III decarboxylase (UROD) localize to the apicoplast.
Phenotype
Normal asexual blood stage growth/multiplication in mice
Additional information
From the Abstract (published in bioRxiv preprint doi: https://doi.org/10.1101/589242. This version posted June 13, 2020):
'A mouse ENU-induced mutagenesis screen for novel malaria resistance-conferring mutations identified a novel nonsense mutation in the gene encoding porphobilinogen deaminase (PBGD) in mice, denoted here as PbgdMRI58155. Heterozygote PbgdMRI58155 mice exhibited approximately 50% reduction in cellular PBGD activity in both mature erythrocytes and reticulocytes, although enzyme activity was approximately 10 times higher in reticulocytes than erythrocytes. When challenged with blood-stage P. chabaudi, which preferentially infects erythrocytes, heterozygote mice showed a modest but significant resistance to infection, including reduced parasite growth.
The Plasmodium resistance phenotype was not recapitulated in Pbgd-deficient mice infected with P. berghei, which prefers reticulocytes, or when P. falciparum was cultured in erythrocytes from patients with acute intermittent porphyria (AIP), which had modest (20-50%) reduced levels of PBGD. Furthermore, the growth of Pbgd-null P. falciparum and Pbgd-null P. berghei parasites, which grew at the same rate as their wild-type counterparts in normal cells, were not affected by the PBGD-deficient background of the AIP erythrocytes or Pbgd-deficient mice'.
Other mutants |