Successful modification | The parasite was generated by the genetic modification |
The mutant contains the following genetic modification(s) |
Gene disruption,
Introduction of a transgene,
Introduction of a transgene
|
Reference (PubMed-PMID number) |
Reference 1 (PMID number) : 31730853 |
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 |
RMgm-1320
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Other information parent line | This transgenic reporter line expresses luciferase under the control of the eef1α (PBANKA_113330) promoter and, in addition, mCherry under the control of the hsp70 (PBANKA_071190) promoter. Both reporter cassetes are introduced into the silent 230p locus, using a single DNA construct. This transgenic line does not contain a drug-selectable marker |
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The mutant parasite was generated by |
Name PI/Researcher | Stanway RR, Janse CJ, Heussler VT (1) |
Name Group/Department | Institute of Cell Biology |
Name Institute | University of Bern |
City | Bern |
Country | Switzerland |
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Name of the mutant parasite |
RMgm number | RMgm-4610 |
Principal name | 2916cl1 |
Alternative name | ΔPGM3 |
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 | Normal fertilisation rate and ookinete production; many mature ookinetes with 'wild type' morphology (light microscopy; Giemsa stained)(but also ookinetes with a somewhat 'bulbous' appearance). |
Oocyst | Strongly reduced oocyst formation. |
Sporozoite | No salivary gland sporozoites. |
Liver stage | See Additional Information: Evidence for a role during liver stage development |
Additional remarks phenotype | Mutant/mutation
The mutant lacks expression of PAGM (PGM3) and expresses mCherry and luciferase under constitutive promoters.
Protein (function)
The gene has been selected based on a predicted role in mosquito- or liver-stage development in a high throughput screen where more than 1300 barcoded P. berghei mutants were followed through the complete life cycle.
Phenotype
Normal fertilisation rate and ookinete production; many mature ookinetes with 'wild type' morphology (light microscopy; Giemsa stained)(but also ookinetes with a somewhat 'bulbous' appearance). Strongly reduced oocyst formation. No salivary gland sporozoites.
Additional information
The gene has been selected based on a predicted role in mosquito- or liver-stage development in a high throughput screen where more than 1300 barcoded P. berghei mutants (PlasmoGem) were followed through the complete life cycle.
Barcodes were quantified in blood stages (B1), midgut oocysts (MG), salivary gland sporozoites (SG) and in blood stages after intravenous infection of mice with sporozoites (B2).
In the different life cycle transitions, barcode quantification was described as not-reduced, reduced or no power. For this gene:
B1-MG: reduced
MG-SG: no power
SG-B2: reduced (-7.8).
Cross-fertilization between different mutants in the mosquito midgut limits the power of the screen to reveal gene functions during the subsequent diploid and polyploid stages (i.e. zygotes, ookinetes and oocysts). For instance, knock-out mutants in which only one sex is sterile, can transmit their barcodes to the oocyst by inheritance through the fertile sex. As a result, reductions in barcode abundance for these sex-specific knock-out mutants often did not reach significance at the B1-MG conversion. Known gene functions in the diploid/polyploid ookinete were also generally not recapitulated in the screen, presumably due to heterozygous rescue as a result of cross-fertilization. While these observations highlight the need for future screens to be designed specifically to reveal sexual and mosquito stage phenotypes, they also rationalize how knock-out alleles of genes functioning in fertility or ookinete/oocyst development can be transmitted to salivary gland sporozoites to reveal additional gene functions after sporozoite transmission to the vertebrate host.
Other mutants |