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

Protein (function)
In a genome-wide study of Plasmodium berghei (Pb) protein phosphatases,  30 phosphatase genes were identified together with one for a predicted protein tyrosine phosphatase-like protein, PbPTPLA, which was shown to be essential for sporozoite formation and completion of the parasite life cycle, but  not fully characterized (Guttery, Poulin et al., 2014).  However, despite the original annotation as an inactive PTP-like protein, more recent functional studies indicate that it is a key component of the VLCFA elongation cycle – more specifically the ELO pathway as a 3-hydroxyacyl-CoA dehydratase (DEH).
P. berghei (PBANKA_1346500) and P. falciparum (Pf; PF3D7_1331600) DEH genes are annotated as PTPLA (pfam04387), the criterion for PTPLA being the presence of a PTP active site motif (CXXGXXR) but with arginine replaced by proline (CXXGXXP). However, CLUSTALW alignment of Pb and Pf protein sequences with the human and mouse HACD1 and HACD2 shows this motif is absent, indicating that Plasmodium DEHs cannot be classified as PTP-like proteins. Furthermore, STRING database analysis predicts that PfDEH interacts with FAE and FAS proteins, and many other proteins with an ER location.

Phenotype
While the overall number of oocysts observed in Δdeh and WT lines was not significantly different, there was a significant reduction in Δdeh GFP-expressing oocysts beginning at day 7 and continuing through day 21 post-infection, with many appearing to be degenerating and were reduced in size compared to wild type oocysts. 
Δdeh oocysts showed numerous cytoplasmic vacuoles with evidence of dilatation of the nuclear membranes.

Additional information
See mutant RMgm-1087 which expresses a C-terminal GFP-tagged version of DEH and is used in this study.

From the paper: 'To determine the expression profile and location of PbDEH, we used a single homologous recombination strategy to tag the 3’ end of the endogenous deh locus with sequence coding for GFP (Guttery, Poulin et al., 2014), and then analyzed blood and mosquito stages of the life-cycle for GFP. Strong GFP fluorescence was observed throughout the life-cycle, with areas of localized expression in the cytoplasm and a circular ring formation around the nucleus. Predotar analysis predicted an ER localization for both PbDEH and PfDEH. Colocalization with ER tracker confirmed the DEH-GFP location at the ER, in all parasite stages analyzed, with subcellular fractionation of blood stage parasites confirming its integral membrane location'.

Other mutants