Malaria parasiteP. berghei
DisruptedGene model (rodent): PBANKA_0401100; Gene model (P.falciparum): PF3D7_0302100; Gene product: serine/threonine protein kinase (SR protein kinase, sprk; sprk1)
Phenotype Asexual bloodstage; Gametocyte/Gamete; Fertilization and ookinete; Oocyst;
Last modified: 18 November 2017, 21:27
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) : 20951971
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/ResearcherR. Tewari, O. Billker
Name Group/DepartmentUniversity of Nottingham
Name InstituteUniversity of Nottingham
Name of the mutant parasite
RMgm numberRMgm-528
Principal nameK46 sprk
Alternative name
Standardized name
Is the mutant parasite cloned after genetic modificationYes
Asexual blood stagemildly reduced growth
Gametocyte/GameteMale gametocytes do not exflagellate; female gametocyte produce fertile gametesas shown by fertilisation with by wild type male gametes (in vitro)
Fertilization and ookineteNo ookinete formation. Male gametocytes do not exflagellate; female gametocyte produce fertile gametesas shown by fertilisation with by wild type male gametes (in vitro)
Oocystno oocysts
SporozoiteNot tested
Liver stageNot tested
Additional remarks phenotype

The gene has been targeted for gene deletion using a construct aimed at integration into the genome by double cross-over homologous recombination

The gene has been targeted for disruption in a 'kinome-wide' study for deletion of genes encoding Plasmodium protein kinases (protein kinase-like proteins).

See the paper for additional information on the analysis of the phenotype.

Disruption of the P. falciparum ortholog has been attempted (Solyakov et al., 2011, Nat Commun, 2:565).
The gene is likely essential for asexual proliferation as integration of the KO vector was not achieved. Accesibility of the locus to recombination was verified by C-terminal tagging.

See also the analyses in PMID: 29141230:

The follwing is mentioned in this paper:
'To place the SRPK1-KO phosphoproteomic results in a broader phenotypic context, we measured DNA replication, axoneme assembly, and exflagellation of the mutant parasites. We found that, by 10 min, a significantly lower percentage of gametocytes had completed three rounds of DNA replication, while a larger percentage remained haploid. SRPK1-KO male gametocytes thus appear affected during the first genome replication, but, if this process completes, no further defects are observed in reaching the octoploid level. Consistently, we observed that parasites that reached the octoploid level successfully assembled axonemes. While neither observation could be accounted for by a change in sex ratio in the mutant parasites, they may be due to some proportion of the microgametocyte  population becoming nonviable during gametocytogenesis. This is tentatively supported by our phosphoproteomic results, which showed marked differences in the SRPK1-KO already at pre-activation. However, the data also revealed significant post-activation effects on phosphorylation, which may account for the observed phenotype. Thus, the kinase is expected to play a regulatory role in the seconds following activation. Furthermore, since microgametocytes lacking SRPK1 completely failed to exflagellate, this kinase is additionally required for fully replicated cells to complete gametogenesis.

  Disrupted: Mutant parasite with a disrupted gene
Details of the target gene
Gene Model of Rodent Parasite PBANKA_0401100
Gene Model P. falciparum ortholog PF3D7_0302100
Gene productserine/threonine protein kinase
Gene product: Alternative nameSR protein kinase, sprk; sprk1
Details of the genetic modification
Inducable system usedNo
Additional remarks inducable system
Type of plasmid/construct used(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
Partial or complete disruption of the genePartial
Additional remarks partial/complete disruption nearly complete
Selectable marker used to select the mutant parasitetgdhfr
Promoter of the selectable markerpbdhfr
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
Additional information primer 1primer sequence target region 1a
Additional information primer 2primer sequence target region 1b
Additional information primer 3primer sequence target region 2a
Additional information primer 4primer sequence target region 2b
Sequence Primer 5
Additional information primer 5
Sequence Primer 6
Additional information primer 6