Mutant/mutation
The mutant  expresses a C-terminal GFP-tagged version of DHHC10 and, in addition, it expresses a C-terminal mCherry-tagged version of LAP3 (PBANKA_0204500). The mCherry-tagged lap3 gene is introduced as an additional copy on a circular plasmid in the mutant that expresses a GFP-tagged version of DHHC10 (RMgm-1472).  The dhhc10::gfp;lap3::mCherry parasites are selected by WR99210 treatment.

Protein (function)
Many proteins are post-translationally modified by the addition of lipids. Palmitoylation results in the addition of a C-16 fatty acid to a cysteine residue within a given protein. Palmitoylation is reversible and thus can dynamically regulate a protein’s subcellular localization, gene expression and activity.
Blocking palmitoylation in P. falciparum with 2-bromopalmitate (2-BMP) results in a complete failure to develop merozoites during the blood stage of the life cycle. Preventing palmitoylation of proteins through targeted mutagenesis of cysteine residues within the modification target results in the mis-localization of proteins found in the inner membrane complex (IMC).
The palmitoylation reaction is catalysed by TM-spanning enzymes called palmitoyl-S-acyl-transferases (PAT). One family of PATs is characterised by the presence of a conserved DH(H/Y)C motif, and certain apicomplexan organisms express more than 10 individual S-acyltransferases. They differ in localisation and timing of expression, and therefore are likely to modify distinct protein populations and biological functions.
The global extent of palmitoylation in asexual blood stages of P. falciparum comprises several hundred proteins; they include factors involved in gliding motility, invasion, adhesion, IMC function, signalling, protein transport and proteolytic activity. Of 11 PATs known from rodent malaria parasites five have been detected in blood stage parasites of P. berghei using an HA-tagging approach: they are DHHC3 (IMC), DHHC5 (ER), DHHC7 (rhoptry), DHHC8 (punctate_not_Golgi), and DHHC9 (IMC). Seven DHHC-PATs were found to be redundant for P. berghei blood stage development in a reverse genetic screen: they are DHHC 3, 5, 6, 7, 9, 10 and 11.
Three PATs are under putative translational control in the female P. berghei gametocyte: dhhc2, dhhc3 and dhhc10.

Phentype analyses of a mutants lacking expression of DHHC10 (RMgm-1470, RMgm-1471) showed the following phenotype: Normal numbers of gametocytes are produced. Normal fertilisation rate and ookinete production. Ookinetes however lack crystalloids (crystalloid body; crystalloid organelle). Normal numbers of oocysts are produced. However, oocysts fail to produce sporozoites.

Attempts to disrupt the dhhc2 gene in P. berghei were unsuccessful (see RMgm-1350) indicating an essential role of DHCC2 for blood stage development/multiplication. Phenotype analyses of the promoter-swap mutant indicate that DHHC2 plays an important role in the development of zygotes into mature ookinetes (RMgm-1349; RMgm-1351). The promoter-swap mutant produced normal numbers of female and male gametocytes and gametes and normal fertilisation rates and production of zygotes. However zygotes failed to develop into mature ookinetes. No oocysts are formed.

Phenotype
Phentype analyses of mutants lacking expression of DHHC10 (RMgm-1470, RMgm-1471) showed the following phenotype: Normal numbers of gametocytes are produced. Normal fertilisation rate and ookinete production. Ookinetes however lack crystalloids (crystalloid body; crystalloid organelle). Normal numbers of oocysts are produced. However, oocysts fail to produce sporozoites.

Phenotype analyses of the mutant expressing GFP-tagged DHHC10 (RMgm-1472) showed GFP-fluorescence in distinct cytoplasmic foci in ookinetes known for members of the LAP/CCp protein family typical for the ookinete/oocyst-specific crystalloid organelle

This mutant showed normal progression throughout the life cycle, including ookinete, oocyst, and sporozoite production and transmission to mice via mosquito bites, indicating that GFP-tagging of DHHC10 did not affect protein function or parasite viability.

Analyses of the dhhc10::gfp;lap3::mCherry mutant showed co-localisation of DHHC10::GFP and LAP3::mCherry in ookinetes. LAP3 has previously been localized to the ookinete crystalloids by both live fluorescence imaging and immunoelectron microscopy. The co-localisation confirms the crystalloid location of DHHC10

Additional information
dhhc10 transcripts are present in female gametocytes but protein is absent. Evidence is presented for translational repression in female gametocytes. The protein is produced after fertilisation in developing zygots/ookinetes. Evidence is presented for a location of DHHC10 in the crystalloid organelles (see also RMgm-1472, RMgm-1474).

Crystalloids are formed by the microtubule (MT)-dependent transport and assembly of endoplasmic reticulum-derived vesicles. Concomitantly, LAP proteins such as LAP3 are shuttled to common assembly points and incorporated into mature crystalloids. DHHC10::GFP was detected as early as 3 h postfertilization, and both DHHC10 and LAP3 showed signs of protein concentration by 9 h postfertilization. At 12 h, more than 50% of the retorts displayed focal accumulation of both proteins, and by the end of ookinete development (24 h), GFP and mCherry signals colocalized in the crystalloid in more than 90% of mature ookinetes. Thus, no significant differences between the two proteins in either the timing of expression or subcellular localization were evident.

Other mutants
See palmitoyltransferase
See DHHC10