Mutant/mutation
The mutant expresses a 3xHA-tagged version of SAS4

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.

Phenotype
In activated male (micro)gamstocytes the eight basal bodies are concomitantly de novo assembled from a deuterosome-like structure, where centrin,  γ-tubulin, SAS4/CPAP and SAS6 form distinct subdomains. Once assembled, the basal bodies show a fusion of the proximal and central cores where  colocalised centrin and SAS6 are surrounded by a SAS4/CPAP-toroid in the lumen of the microtubule wall. 

Additional information

Other mutants