Mutant/mutation
The mutant Δc01 lacks expression of PIMMS01 and expresses GFP under control of the constitutive eef1a promoter

Protein (function)
PfPIMMS01 encodes a 163 amino acid-long protein (19 kDa) with a predicted signal peptide (aa 1–27). Its P. berghei orthologue, PbPIMMS01, encodes a much shorter 85 amino acid-long protein (9 kDa) and also contains a predicted signal peptide (aa 1–26). This suggests that both proteins are putatively secreted. While the central part of the deduced protein is highly conserved between all PIMMS01 orthologues, all rodent PIMMS01 proteins are shorter than their orthologues in human parasites, lacking the entire second half of the protein. InterPro domain analysis revealed no recognizable domain, and BLAST searches showed that the protein is Plasmodium specific.  

Phenotype
Ookinete motility comparable to wild type. No evidence for ookinete defects in invasion and traversal of the midgut epithelium. Strongly reduced oocyst numbers. Strongly reduced sporozoite numbers. No infection of mice by the bite of infected mosquitoes.
(injection of mature ookinetes into the thorax partly rescued the sporozoite phenotype)

Additional information
Three genes were selected for analysis that exhibit highly abundant transcripts 24 h post blood feeding in the midguts of Anopheles coluzzii mosquitoes.
 
PIMMS01: PF3D7_0112100; PBANKA_0201700 
PIMMS57: PF3D7_1244500; PBANKA_1457700
PIMMS22: PF3D7_0814600; PBANKA_1422900 
((PIMMS: Plasmodium Infection of the Mosquito Midgut Screen)

Names of the corresponding gene-deletion mutants: Δc01, Δc57, Δc22

PbPIMMS01 and PbPIMMS57 transcripts were highly abundant in purified mature ookinetes and not detectable in mixed blood stages and purified gametocytes. While PbPIMMS57 appears to be specific for ookinetes, low levels of PbPIMMS01 transcripts are also detected in mature oocysts and midgut sporozoites at 10 days and 15 days post blood-feeding. Like PfPIMMS22, expression of PbPIMMS22 starts in gametocytes and continues at high levels at 24 hour and peaks in midgut sporozoites at day 15

From the abstract:
PIMMS01 and PIMMS57 are specifically and highly expressed in ookinetes, while PIMMS22 transcription starts already in gametocytes and peaks in sporozoites. All three genes show strong phenotypes associated with the ookinete to oocyst transition, as their disruption leads to very low numbers of oocysts and complete abolishment of transmission. PIMMS22 has a secondary essential function in the oocyst. 

Other mutants