Mutant/mutation
The mutant expresses a C-terminal GFP-tagged version of kinesin-8B

Protein (function)
Proteomic analysis has revealed many potential regulators of axoneme assembly present in male gametes, including members of the kinesin superfamily. Kinesins are molecular motor proteins that have essential roles in intracellular transport, cell division, and motility. Some kinesin families are known to contribute to the ciliary structure and function, either by transporting ciliary components along axonemal  microtubules (MTs) by IFT such as kinesin-2s, or by destabilizing MTs, such as kinesin-9 and kinesin-13. Kinesin-8s are conserved from protozoa to mammals, and can be subclassified as kinesin-8A, -8B and -8X. In general, kinesin-8s are multitasking motors, able to move along MTs, cross-link and slide MTs, and influence MT dynamics at their ends.  Kinesin-8As are best characterised as regulators of spindle length and chromosome positioning during metaphase, whereas the mammalian kinesin-8B (Kif19) has a role in ciliary length control. The Plasmodium genome encodes two kinesin-8s (kinesin-8X and kinesin-8B), along with six or seven other kinesin proteins. Kinesin-8X is conserved across the Apicomplexa, whereas kinesin-8B is restricted to certain genera such as Toxoplasma, Eimeria, and Plasmodium that have flagellated gametes. 

Phenotype
The expression and location of kinesin-8B was assessed by live cell imaging throughout the parasite life cycle; it was not observed in most stages except male gametocytes and gametes.

Phenotype analyses of a mutant lacking expression of kinesin-8B (RMgm-4673) showed the following: Normal numbers of male/female gametocytes are formed. No male gamete formation (exflagellation). No ookinete and oocyst formation.

Additional information
To establish whether kinesin-8B is part of the mitotic assembly during the three rounds of chromosome replication in male gamete development, we examined its location together with that of the kinetochore protein Ndc80. Parasite lines expressing kinesin-8B–GFP and Ndc80-cherry were crossed and used for live cell imaging of both markers to establish their spatiotemporal relationship. 1–2 min after gametocyte activation, kinesin-8B was observed close to the nucleus and adjacent to Ndc80, but not overlapping with it. This pattern of adjacent location is also seen in later stages of development. This shows that both axoneme formation and chromosome division begin at a very early stage of gametogenesis and continue side by side 

Evidence is presented for the following:
- Kinesin-8B is not required for DNA replication in activated male gametocytes, but its deletion impairs male exflagellation
- Activated Δkinesin-8B gametocytes lack the 9+2 microtubules (MTs) axoneme architecture. Ddeletion of the kinesin-8B gene did not appear to affect the initiation, growth, or density of single and doublet MTs but completely prevented their organisation into 9+2 axonemes. In addition, there was a reduction in the number of basal bodies and, more markedly, in their association with the nuclear poles. This defect ultimately prevented exflagellation and the formation of viable male gametes.
- Spatiotemporal profiles of kinesin-8B and the kinetochore protein Ndc80 show that kinesin-8B is absent from the mitotic spindle. 
- Kinesin-8B was localised on cytoplasmic MTs rather than on spindle MTs during male gamete formation
- Kinesin-8B associates dynamically with basal bodies and growing axonemes 

Other mutants