Mutant/mutation
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.

Phenotype
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.