Mutant/mutation
In the mutant the endogenous P. berghei akratin gene has been replaced with the P. falciparum akratin gene that is C-terminally GFP-tagged. The GFP-tagged P. falciparum akratin gene has been introduced into the akratin locus of a mutant (see RMgm-4885) in which the akratin gene has been deleted.

Protein (function)
PbANKA_1105300 was found to be conserved among Plasmodium spp. It shares 82% identity with its orthologue in P. yoelii, but only 35% and 32% with its orthologues in P. falciparum and P. vivax, respectively. In contrast to P. berghei and P. falciparum, the orthologues in P. yoelii and P. vivax are predicted to contain only two TMDs. Furthermore, the P. falciparum protein contains about two times more amino acids than the P. berghei protein. No orthologue was found outside Plasmodium spp

Phenotype
A mutant lacking expression of akratin (see mutant RMgm-4885) fails to produce male gametes (and ookinetes and oocysts)

The normal production of ookinetes and oocysts of mutants expressing P. falciparum akratin shows that the P. falciparum orthologue is  functional in P. berghei even though it has a long N-terminal extension and an overall identity of only 35%

Additional information
In this study also a mutant has been generated that expresses a C-terminal GFP-tagged version of P. berghei akratin. The following evidence is presented on akratin expression and localisation:
'We next investigated the localization of the fluorescent signal in the blood stage and the extracellular forms of the life cycle. This revealed a mostly diffuse signal with some punctae in blood stages of both parasite lines expressing the P. falciparum or P. berghei akratin-GFP. In non-activated gametocytes the signal was distributed within the gametocyte cytoplasm but it was much weaker in the P. falciparum akratin-GFP line, where it appeared punctate. No difference between male and female gametocytes could be observed. However, upon activation two distinct populations, most likely males and females could be observed. While in females the protein was distributed in the cytoplasm of the cell, male (determined by a cloudy Hoechst staining) showed one bright spot in addition to a few weak dots at the periphery. Ookinetes showed a vesicular/endomembranous staining with a prominent peripheral staining for the P. berghei akratin-GFP but an exclusively vesicular pattern for the P. falciparum akratin- GFP. Sporozoites isolated from the oocysts or salivary glands showed a similar punctate localization for both lines reminiscent of secretory vesicles but distinct from the strong apical signal seen in GFP-TRAP sporozoites 

Other mutants