Mutant/mutation
The mutant lacks expression of OMD

Protein (function)
MD was as highlighted in a group of motility and invasion-related genes such as gap45, tlp1, celtos and spect2, whose transcription was rapidly downregulated during sporozoite to liver stage development.
The gene has five exons and encodes a 176 amino acids long protein with a predicted N-terminal signal peptide. The protein is highly conserved within the Plasmodium genus.

Phenotype
Ookinete formation did not reveal a significant difference between mutant and WT parasite development  with ookinete morphologies similar as revealed by Giemsa-stained smears and scanning electron microscopy analysis. Ookinetes were also formed in vivo as revealed by Giemsa stained smears of mosquito midguts formed 24 h after feeding on an infected mouse.
Mature omd(-) ookinetes were completely devoid of productive motility; at most they displayed stretching of the ookinete.
In vivo transmission experiments, where mosquitoes are allowed to blood feed on mice infected with the omd(-)cl1 mutant, did not result in the establishment of oocysts in three independent feedings; WT parasites on the other hand transmitted normally. No oocyst and sporozoite formation. No transmission to mice by bite of infected mosquitoes.

Additional information
Analysis of a mutant expressing a C-terminal GFP-tagged version of OMD (RMgm-4689) showed the following:
Consistent with the RT-PCR data, fluorescence was apparent in gametocytes, ookinetes and oocysts, as well as in midgut and salivary gland sporozoites, but never detected in asexuals of the omd::gfp line. The OMD::GFP signal appeared mostly uniform and cytoplasmic. Western blot analysis showed that the fusion protein had the expected molecular weight of 48 kDa . We verified that omd::gfp parasites transmitted readily into the mosquito vector, showing that the tag did not interfere with the normal function of the protein; the omd::gfp parasite line produced an average of 6500 salivary gland sporozoites (n = 20) compared to 9450 (n = 25) in the WT control infection.

Evidence is presented for absence of expression of OMD in asexual blood stages and in liver stages.

Evidence is presented that  the failure of ookinete motility in the omd(-) mutant is not due to gross mis-localization of either micronemal proteins or components of the motility machinery.

Other mutants
a mutant expressing a C-terminal GFP-tagged version of OMD (RMgm-4689)