| 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) : 27600503
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| 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 |
Not applicable
|
| Other information parent line | |
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| The mutant parasite was generated by |
| Name PI/Researcher | Rizopoulos Z, Matuschewski K, Haussig J. |
| Name Group/Department | Parasitology Unit |
| Name Institute | Max Planck Institute for Infection Biology |
| City | Berlin |
| Country | Germany |
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| Name of the mutant parasite |
| RMgm number | RMgm-1585 |
| Principal name | pbgd(-) |
| 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 tested |
| Fertilization and ookinete | Not different from wild type |
| Oocyst | Normal numbers of oocysts are formed. However, day 10 and 14 oocysts had a reduced size (`60%) compared to wild type oocysts. A large (~10-20-fold) reduction in the numbers of midgut-associated sporozoites was observed. No hemocoel or salivary gland sporozoites were detected. |
| Sporozoite | Normal numbers of oocysts are formed. However, day 10 and 14 oocysts had a reduced size (`60%) compared to wild type oocysts. A large (~10-20-fold) reduction in the numbers of midgut-associated sporozoites was observed. No hemocoel or salivary gland sporozoites were detected. |
| Liver stage | A large (~10-20-fold) reduction in the numbers of midgut-associated sporozoites was observed. No hemocoel or salivary gland sporozoites were detected. No mosquito transmission. |
| Additional remarks phenotype | Mutant/mutation
The mutant lacks expression of PBGD and expresses GFP under control of the strong hsp70 promoter
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
Mutant parasites showed normal blood stage development, indicating a non-essential role of PBGD during blood stage development. Normal numbers of oocysts are formed. However, day 10 and 14 oocysts had a reduced size (`60%) compared to wild type oocysts. A large (~10-20-fold) reduction in the numbers of midgut-associated sporozoites was observed. No hemocoel or salivary gland sporozoites were detected.
Additional information
In this study, the essentiality of heme biosynthesis was systematically profiled by targeted gene deletion of enzymes in early steps of this pathway. It was shown that disruption of endogenous heme biosynthesis leads to a first detectable defect in oocyst maturation and sporogony in the Anopheles vector, whereas blood stage propagation, colonization of mosquito midguts or initiation of oocyst development occurs indistinguishable from wild-type parasites. Although sporozoites are produced by parasites lacking an intact pathway for heme biosynthesis, they are absent from mosquito salivary glands, indicative of a vital role for heme biosynthesis only in sporozoite maturation.
Rescue of the first defect in sporogony permitted analysis of potential roles in liver stages (see RMgm-1582). It was shown that liver stage parasites benefit from, but do not strictly depend upon their own aminolevulinic acid synthase and that they can scavenge aminolevulinic acid from the host environment.
Other mutants |
*RMgm-1585
