Mutant/mutation
The mutant expresses a cmyc-tagged (C-terminal) form of FABI.

Protein (function)
FABI is an enzyme of the bacterial like type II fatty acid biosynthesis (FAS-II) pathway. In Plasmodium FAS-II enzymes have been localized to the apicoplast, a nonphotosynthetic plastid organelle of cyanobacterial origin.
FAS-II requires acetyl-Coenzyme A (CoA), which can be converted from pyruvate by the pyruvate dehydrogenase complex. Acetyl-CoA carboxylase converts acetyl-CoA to malonyl-CoA, which is tethered to an acyl carrier protein (ACP) by malonyl-CoA:ACP transacylase (FabD). This produces malonyl-ACP, which, in conjunction with acetyl-CoA, is acted upon by β-ketoacyl-ACP synthase III (Fab H) to form β-ketoacyl-ACP. This precursor enters the FAS-II elongation cycle, mediated by FabB/F (β-ketoacyl-acyl-carrier-protein (ACP) synthase), FabG (β-ketoacyl-ACP reductase), FabZ/A (β-hydroxyacyl-ACP dehydratase), and FabI (trans-2-enoyl-ACP reductase). These four FAS-II enzymes iteratively catalyze the addition of two carbon chains to a growing fatty acyl carbon chain via condensation, reduction, dehydration, and reduction steps, respectively.

Phenotype
FabI-myc expression was first detected in salivary gland sporozoites and localized to a spherical structure close to the nucleus. To analyse FabI expression during liver stage development, HepG2:CD81 hepatoma cells were infected with sporozoites . At 7 h post infection when intracellular sporozoites initiate transformation to trophozoites, apicoplast morphology as determined by FabI-myc staining,  was similar to that of salivary gland sporozoites. At 14 h, parasite nuclear division commenced and the apicoplast initiated its division as indicated by the dumbbell shape. By 24 h, the apicoplast had formed a branched lariat-shaped structure, which became more elaborate with advanced liver stage development at 30 h. By 40 h the apicoplast had differentiated into hundreds of intertwining structures that appeared to be segregating. These results show that FabI expression is initiated in salivary gland sporozoites and that there is robust apicoplast-specific FabI expression throughout liver stage development. At 48 h a time point when the P. yoelii liver stage schizont undergoes merozoite formation, FabI-myc expression was greatly reduced when compared with 40 h. This strongly suggests that FabI expression is downregulated shortly before or during exo-erythrocytic merozoite formation. FabI expression could not be detected in blood stages. 

Additional information
The phenotype analyses of a mutant that lacks expression of  FABI (RMgm-197) indicates that FABI is not essential for blood stage development and mosquito stage development. These analyses indicate an essential role of FABI in the formation of infective liver stage merozoites demonstrating the importance of FASII pathway for synthesis of fatty acids during late liver stage development.

Other mutants
RMgm-181: A mutant expressing myc tagged FABZ
RMgm-182: A mutant expressing myc tagged FABG
RMgm-183: A mutant lacking expression of FABB/F
RMgm-197: A mutant lacking expression of FABI
RMgm-184: A mutant lacking expression of FABZ