Mutant/mutation
In the 'promoter swap' mutant is the promoter of the endogenous flp gene replaced by the promoter of clag (PBANKA_1400600).
The mutant expresses a C-terminal HA-tagged version of FLP (since the promoter swap was made in mutant RMgm-4578 (FLP::HA(820)), that expresses a HA-tagged version of FLP). In addition, the mutants expresses GFP under control of a male and RFP under control of a female gametocyte specific promoter.

Protein (function)
The P. berghei ferlin-like protein (FLP, PBANKA_1224400) contains six predicted C2 domains, a C-terminal transmembrane domain and a Fer domain (a ferlin-specific motif of unknown function). These typical features cluster FLP together with ferlin (PBANKA_1319300) into the ferlin protein family.Ferlins are typically embedded in vesicular membranes via a single, C-terminal transmembrane domain with the N-terminus of the protein facing the cytosol.' Negative attempts to disrupt FLP (RMgm-4576) indicates an essential role during growth/multiplication of asexual stages.
Ferlins are established mediators of calcium-induced membrane fusion and regulated exocytosis in higher eukaryotes


Phenotype
FLP is essential for blood stage development/multiplication (see RMgm-4576) for unsuccessful attempts to disrupt the flp gene). In the 'promoter-swap' mutant the promoter of flp is replaced by an 'asexual blood stage’ promoter that is silent (or has a strongly reduced activity) in gametocytes (the promoter of clag, PBANKA_1400600).

In the mutant expression of FLP::HA was clearly depleted in gametocytes. Normal gametocyte production. No ookinete formation (large numbers of unfertilised gametocytes). Mature male and female gametocytes/gametes failed to egress from their host red blood cell, thereby preventing fertilisation. No oocyst/sporozoite formation.

Additional information
Evidence is presented that:
- both PVM and the red blood cell membrane are not ruptured in activated gametocytes of the mutant.
- FLP relocalizes to the cell peripery during activation of gametocytes

From the paper:
'To  assess  whether  FLP  co-localizes  with  these  previously  published  egress  factors G377 (PBANKA_1463000) and PPLP2 (PBANKA_1432400),  we  generated flp::HA;g377::mCherry  and  flp::HA;pplp2::mCherry  double  mutants,  in  which FLP is endogenously tagged with HA while G377 and PPLP2 are endogenously tagged with mCherry, respectively. Neither of the lines showed co-localization between FLP and either of the two proteins, arguing against FLP localization to the G377-positive OBs or to the PPLP2-positive egress vesicles.' 
 
Other mutants