Successful modification | The parasite was generated by the genetic modification |
The mutant contains the following genetic modification(s) |
Gene disruption
|
Reference (PubMed-PMID number) |
Reference 1 (PMID number) : 23935500 |
MR4 number |
|
top of page |
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 | |
top of page |
The mutant parasite was generated by |
Name PI/Researcher | Nagaraj, VA; Padmanaban, G. |
Name Group/Department | Department of Biochemistry |
Name Institute | Indian Institute of Science |
City | Bangalore |
Country | India |
top of page |
Name of the mutant parasite |
RMgm number | RMgm-925 |
Principal name | PbFCKO |
Alternative name | |
Standardized name | |
Is the mutant parasite cloned after genetic modification | Yes |
top of page |
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 | Strongly reduced oocyst production |
Sporozoite | Strongly reduced oocyst and no sporozoite production.
Mice remained negative when infected by mosquito bite or after i.v. injection of sporozoites (see also additional remarks phenotype) |
Liver stage | Strongly reduced oocyst and no sporozoite production. |
Additional remarks phenotype | Mutant/mutation
The mutant lacks expression of ferrochelatase (FC)
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 whereas, the next enzyme Coproporphyrinogen III oxidase (CPO) is cytosolic. Earlier studies showed that host ALAD and FC are imported into the parasites in the intraerythrocytic stages, suggesting that the host machinery may augment parasite heme synthesis.
Phenotype
Mutant parasites showed normal blood stage development, indicating a non-essential role of FC during blood stage development (and for gametocyte and ookinete production). Mutant parasites showed strongly reduced oocyst and no sporozoite production .
Additional information
Evidence is presented that blood stage parasites incorporated both host hemoglobin-heme and parasite-synthesized heme into hemozoin and mitochondrial cytochromes. The similar fates of the two heme sources suggest that they may serve as backup mechanisms to provide heme in the intraerythrocytic stages. Evidence is presented that de novo pathway is essential for parasite development in the mosquito and liver stages. PbKO parasites formed strongly reduced oocysts and did not form sporozoites in the salivary glands.
Oocyst production in PbALASKO parasites (RMgm-924) recovered when mosquitoes received an ALA supplement. PbALASKO sporozoites could infect mice only when the mice received an ALA supplement.
Other mutants
RMgm-924: A mutant lacking expression of delta-aminolevulinic acid synthetase (ALAS; PBANKA_145920) |