RMgmDB - Rodent Malaria genetically modified Parasites

Summary

RMgm-4919
Malaria parasiteP. berghei
Genotype
MutatedGene model (rodent): PF3D7_0408700; Gene model (P.falciparum): PF3D7_0408700; Gene product: perforin-like protein 1 (PLP1, PPLP1, SPECT2)
Details mutation: The endogenous P. berghei plp1/spect2 gene replaced with the P. falciparum plp1/spect2 ortholog
Transgene
Transgene not Plasmodium: GFP (gfp-mut3)
Promoter: Gene model: PBANKA_1133300; Gene model (P.falciparum): PF3D7_1357100; Gene product: elongation factor 1-alpha (eef1a)
3'UTR: Gene model: PBANKA_0719300; Gene product: bifunctional dihydrofolate reductase-thymidylate synthase, putative (dhfr/ts)
Replacement locus: Gene model: PBANKA_0306000; Gene product: 6-cysteine protein (230p)
Phenotype Sporozoite; Liver stage;
Last modified: 13 July 2021, 11:15
  *RMgm-4919
Successful modificationThe parasite was generated by the genetic modification
The mutant contains the following genetic modification(s) Gene mutation, Introduction of a transgene
Reference (PubMed-PMID number) Reference 1 (PMID number) : 34252120
MR4 number
Parent parasite used to introduce the genetic modification
Rodent Malaria ParasiteP. berghei
Parent strain/lineP. berghei ANKA
Name parent line/clone RMgm-4918
Other information parent lineThis line (RMgm-4918, 3144cl3) contains as a selectable marker (SM) the fusion gene of hdhfr (human dihydrofolate reductase; positive SM) and yfcu (yeast cytosine deaminase and uridyl phosphoribosyl transferase; negative SM) stably integrated into the plp1/spect2 locus (PBANKA_0808100) through double cross-over recombination. The SM is under control of the P. berghei eef1α promoter.
The mutant parasite was generated by
Name PI/ResearcherKolli SK, Salman AM, Hill AVS, Janse CJ
Name Group/DepartmentMalaria research group, Department of Parasitology
Name InstituteLeiden University Medical Center, LUMC
CityLeiden
CountryThe Netherlands
Name of the mutant parasite
RMgm numberRMgm-4919
Principal name3162cl2
Alternative name
Standardized name
Is the mutant parasite cloned after genetic modificationYes
Phenotype
Asexual blood stageNot different from wild type
Gametocyte/GameteNot different from wild type
Fertilization and ookineteNot different from wild type
OocystNot different from wild type
SporozoiteNormal numbers of sporozoites; P. falciparum transgene expression in sporozoites; sporozoites have reduced infectivity (as shown by reduced or absence of parasite liver loads after intravenous injection of sporozoites and absence of blood-stage infection or prolonged prepatent period)
Liver stageSporozoites have reduced infectivity (as shown by reduced or absence of parasite liver loads after intravenous injection of sporozoites and absence of blood-stage infection or prolonged prepatent period)
Additional remarks phenotype

Mutant/mutation
The mutant expresses P. falciparum PLP1/SPECT2. The P. falciparum plp1/spect2 gene is introduced into the endogenous P. berghei plp1/spect2 gene locus (by GIMO transfection of line 3144cl3) and is under control of the Pb plp1/spect2 regulatory 3'- and 5'-UTR sequences. It does not contain a drug selectable marker 

The mutant has been generated and selected using the GIMO transfection method ('gene insertion/marker out') of transfection of a 'GIMO line' that contains the hdhfr::yfcu selectable marker into the b9 locus.

Protein (function)

Phenotype
Normal numbers of sporozoites; P. falciparum transgene expression in sporozoites; sporozoites have reduced infectivity (as shown by reduced or absence of parasite liver loads after intravenous injection of sporozoites and absence of blood-stage infection or prolonged prepatent period).

The failure to establish a liver infection like wild type parasites, indicates that expression of the P. falciparum protein in sporozoites has a negative impact of on sporozoite infectivity/establishment of a liver infection.

In this study 14 transgenic P. berghei parasites were generated that express P. falciparum proteins that are expressed in the sporozoite/liver stage of P. falciparum.
Six of these chimeric P. berghei parasites that produce infective sporozoites have been used in a challenge model to test the protective efficacy of novel P. falciparum viral vectored vaccine candidate antigens. Mice were immunized with the P. falciparum vaccine candidates, followed by  challenge with the transgenic P. berghei sporozoites.

Expression of the P. falciparum antigens in the transgenic sporozoites was analysed by immunofluorescence assay (using serum from vaccinated mice)  

Additional information


Other mutant
See the link for the other 14 transgenic P. berghei lines expressing P. falciparum proteins that were generated in this study


  Mutated: Mutant parasite with a mutated gene
Details of the target gene
Gene Model of Rodent Parasite PF3D7_0408700
Gene Model P. falciparum ortholog PF3D7_0408700
Gene productperforin-like protein 1
Gene product: Alternative namePLP1, PPLP1, SPECT2
Details of the genetic modification
Short description of the mutationThe endogenous P. berghei plp1/spect2 gene replaced with the P. falciparum plp1/spect2 ortholog
Inducable system usedNo
Short description of the conditional mutagenesisNot available
Additional remarks inducable system
Type of plasmid/construct(Linear) plasmid double cross-over
PlasmoGEM (Sanger) construct/vector usedNo
Modified PlasmoGEM construct/vector usedNo
Plasmid/construct map
Plasmid/construct sequence
Restriction sites to linearize plasmid
Selectable marker used to select the mutant parasitehdhfr/yfcu
Promoter of the selectable markereef1a
Selection (positive) procedureNo
Selection (negative) procedure5-fluorocytosine (5-FC)
Additional remarks genetic modificationThe ‘replacement’ chimeric parasite line expressing PfSPECT2 (PF3D7_0408700) was generated using the 2-step GIMO transfection protocol. In the first step, the Pbspect2 ORF (PBANKA_1006300) was replaced with the positive-negative hdhfr::yfcu SM to create a Pbspect2 deletion GIMO line (PbΔspect2). This was achieved by generating a DNA construct pL2318, that has 5’ and 3’ targeting regions of Pbspect2 ligated in GIMO DNA construct pL0034. Plasmid pL2318 was linearized with ApaI/NotI and transfected into parasites of 676cl1 parasites using standard methods of transfection. PbΔspect2 parasites (line 3144) were selected by positive selection providing pyrimethamine in the drinking water of mice. Transfected parasites were cloned by limiting dilution, and correct integration of the targeting constructs were analyzed by diagnostic PCR analysis of gDNA and Southern analysis of PFG-separated chromosomes as described. In the second step, we replaced the hdhfr::yfcu SM in PbΔspect2 with the Pfspect2 ORF by GIMO transfection to create a chimeric Pb-Pfspect2(r) replacement line. This was achieved by replacing the hdfhr::yfcu SM in pL2318 with the Pfspect2 ORF sequence, generating plasmid pL2319. The Pfspect2 ORF was PCR-amplified from PfNF54 genomic DNA, digested with SacII/KpnI and ligated into vector pL2318 to obtain pL2319. The construct was linearized using ApaI and NotI restriction enzymes and transfected into PbΔspect2 (line 3144cl3) by standard methods of GIMO transfection. Transfected parasites (line 3162) were selected in mice by applying negative selection by providing 5-fluorocytosine (5-FC) in the drinking water. Negative selection results in the selection of chimeric parasites where the hdhfr::yfcu SM locus is replaced by Pfspect2 ORF Selected chimeric parasites were cloned by limiting dilution
Additional remarks selection procedureIn the mutant the negative/positive hdhfr/yfcu selectable marker cassette (in the parent 3144cl3 line) has been replaced by the P. falciparum plp1/spect2 expression cassette
Primer information: Primers used for amplification of the target sequences  Click to view information
Primer information: Primers used for amplification of the target sequences  Click to hide information
Sequence Primer 1
Additional information primer 1
Sequence Primer 2
Additional information primer 2
Sequence Primer 3
Additional information primer 3
Sequence Primer 4
Additional information primer 4
Sequence Primer 5
Additional information primer 5
Sequence Primer 6
Additional information primer 6

  Transgene: Mutant parasite expressing a transgene
Type and details of transgene
Is the transgene Plasmodium derived Transgene: not Plasmodium
Transgene nameGFP (gfp-mut3)
Details of the genetic modification
Inducable system usedNo
Additional remarks inducable system
Type of plasmid/construct(Linear) plasmid double cross-over
PlasmoGEM (Sanger) construct/vector usedNo
Modified PlasmoGEM construct/vector usedNo
Plasmid/construct map
Plasmid/construct sequence
Restriction sites to linearize plasmid
Selectable marker used to select the mutant parasitegfp (FACS)
Promoter of the selectable markereef1a
Selection (positive) procedurepyrimethamine
Selection (negative) procedureNo
Additional remarks genetic modification
Additional remarks selection procedure
Other details transgene
Promoter
Gene Model of Parasite PBANKA_1133300
Gene Model P. falciparum ortholog PF3D7_1357100
Gene productelongation factor 1-alpha
Gene product: Alternative nameeef1a
Primer information details of the primers used for amplification of the promoter sequence  Click to view information
Primer information details of the primers used for amplification of the promoter sequence  Click to hide information
Sequence Primer 1
Additional information primer 1
Sequence Primer 2
Additional information primer 2
3'-UTR
Gene Model of Parasite PBANKA_0719300
Gene productbifunctional dihydrofolate reductase-thymidylate synthase, putative
Gene product: Alternative namedhfr/ts
Primer information details of the primers used for amplification the 3'-UTR sequences  Click to view information
Primer information details of the primers used for amplification the 3'-UTR sequences  Click to hide information
Sequence Primer 1
Additional information primer 1
Sequence Primer 2
Additional information primer 2
Insertion/Replacement locus
Replacement / InsertionReplacement locus
Gene Model of Parasite PBANKA_0306000
Gene product6-cysteine protein
Gene product: Alternative name230p
Primer information details of the primers used for amplification of the target sequences  Click to view information
Primer information details of the primers used for amplification of the target sequences  Click to hide information
Sequence Primer 1
Additional information primer 1
Sequence Primer 2
Additional information primer 2
Sequence Primer 3
Additional information primer 3
Sequence Primer 4
Additional information primer 4