RMgmDB - Rodent Malaria genetically modified Parasites


Malaria parasiteP. berghei
DisruptedGene model (rodent): PBANKA_0106200; Gene model (P.falciparum): PF3D7_0607600; Gene product: spindle assembly abnormal protein 6, putative (SAS6)
Phenotype Gametocyte/Gamete;
Last modified: 2 February 2022, 15:38
Successful modificationThe 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) : 35077503
MR4 number
Parent parasite used to introduce the genetic modification
Rodent Malaria ParasiteP. berghei
Parent strain/lineP. berghei ANKA
Name parent line/clone P. berghei ANKA 2.34
Other information parent lineP. berghei ANKA 2.34 is a cloned, gametocyte producer line of the ANKA strain (PubMed: PMID: 15137943).
The mutant parasite was generated by
Name PI/ResearcherRashpa R, Brochet M
Name Group/DepartmentDepartment of Microbiology and Molecular Medicine, Faculty of Medicine
Name InstituteUniversity of Geneva
Name of the mutant parasite
RMgm numberRMgm-5154
Principal nameSAS6-KO
Alternative name
Standardized name
Is the mutant parasite cloned after genetic modificationYes
Asexual blood stageNot tested
Gametocyte/GameteWe first confirmed the importance of SAS6 in microgametogenesis as no exflagellation centres were observed 15 min post-activation in the SAS6-KO line, as previously described
Fertilization and ookineteNot tested
OocystNot tested
SporozoiteNot tested
Liver stageNot tested
Additional remarks phenotype

The mutant lacks expression of SAS6

Protein (function)
The mature microgametocyte shows two electron-dense structures that have been linked with the formation of the mitotic spindles and the axonemes,  respectively. One of this structure was described as an amorphous MTOC lying on the cytoplasmic face of a nuclear pore that is  physically linked to another electron dense aggregation called the intranuclear  body in the nuclear face of the same pore. Upon activation of gametogenesis, the amorphous MTOC gives rise to eight basal bodies on which axonemes are nucleated,  while the intranuclear body likely corresponds to the so- called centriolar plaques (also called spindle poles or centrosomes).  The basal bodies of the forming axonemes remain attached to their respective centriolar plaque 68 during the three following mitoses and are moved  around the nuclear envelope at each round of division. Despite coding for four centrins, the Plasmodium genomes lack many conserved components of the basal body except SAS6, SAS4/CPAP and CEP135.  A P. berghei SAS6-KO clone displayed reduced basal body numbers, axonemal assembly defects and abnormal nuclear allocation.

We first confirmed the importance of SAS6 in microgametogenesis as no exflagellation centres were observed 15 min post-activation in the SAS6-KO line, as previously described.

Evidence is presented that suggest that SAS6 is essential for the de novo formation of the eight basal bodies but is also required to maintain the structural integrity of the gametocyte MTOC required for the transition between mitosis I and II.

Additional information
In the paper also a SAS4-KO mutant is generated:
Deletion of sas4 led to a 90% decrease in the formation of active exflagellation centres.

Evidence is presented that suggest that SAS4 is not essential for axoneme formation, however, its absence leads to defects in the molecular organisation of the basal body during the course of microgametogenesis.

Other mutants

  Disrupted: Mutant parasite with a disrupted gene
Details of the target gene
Gene Model of Rodent Parasite PBANKA_0106200
Gene Model P. falciparum ortholog PF3D7_0607600
Gene productspindle assembly abnormal protein 6, putative
Gene product: Alternative nameSAS6
Details of the genetic modification
Inducable system usedNo
Additional remarks inducable system
Type of plasmid/construct used(Linear) PCR construct double cross-over
PlasmoGEM (Sanger) construct/vector usedYes
Name of PlasmoGEM construct/vectorPbGEM-327715
Modified PlasmoGEM construct/vector usedNo
Plasmid/construct map
Plasmid/construct sequence
Restriction sites to linearize plasmid
Partial or complete disruption of the geneComplete
Additional remarks partial/complete disruption
Selectable marker used to select the mutant parasitehdhfr/yfcu
Promoter of the selectable markereef1a
Selection (positive) procedurepyrimethamine
Selection (negative) procedureNo
Additional remarks genetic modification
Additional remarks selection procedure
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