Additional remarks phenotype | Mutant/mutation
The mutant lacks expression of PbANKA_1422100
Protein (function)
The protein was identified in a bioinformatic screen for identifying apicoplast proteins.
27 candidate apicoplast membrane proteins were identified, 20 of which are annotated as putative membrane transporters.
Candidates were selected from P. falciparum putative membrane transporters belonging to known transport families and selected members of the predicted P. falciparum apicoplast proteome with multiple TMDs. Many P. falciparum membrane transporters have seven or more TMDs, whilst some have six or fewer. Without biological data to confirm membrane transport activity, candidate proteins predicted to have at least six TMDs were selected. Although multiple TMDs is a minimum requirement of most membrane transporters, some of these proteins may be integral membrane proteins with other functions.
A genetic screen was performed in P. berghei to determine blood stage essentiality and subcellular localisation. Eight apparently essential blood stage genes were identified, three of which were apicoplast-localised: PbANKA_0614600 (DMT2), PbANKA_0401200 (ABCB4) and PbANKA_0505500. Nineteen candidates could be deleted at the blood stage, four of which were apicoplast-localised.Three apicoplast-localised candidates lack a canonical apicoplast targeting signal but do contain conserved N-terminal tyrosines with likely roles in targeting.
Sixteen candidate genes were HA-tagged for localisation experiments in P. berghei.
Immunofluorescence assays (IFAs) were performed for all tagged candidate genes. Five candidates co-localised with the apicoplast marker, ACP. PbANKA_0809500, PbANKA_0401200, PbANKA_0505500 were all predicted to have apicoplast targeting leader sequences whilst PbANKA_1103600, PbANKA_1304700 were not predicted to contain leader sequences. Another seven candidates localised to non-apicoplast structures within the parasite. Four candidates had no observable immunofluorescence signal at the blood stage so could not be localised in this life cycle stage: PbANKA_0942100, PbANKA_0417100, PbANKA_1446100 and PbANKA_0602400. Life cycle analysis of two candidates (PbANKA_1103600 and PbANKA_0942100) revealed that PbANKA_1103600 TAG was expressed and localised to the apicoplast in midgut oocysts, salivary gland sporozoites and in vitro liver cell stage parasites. No signal was observed for PbANKA_0942100 TAG parasites at any life cycle stage so its localisation remains unknown
Phenotype
Evidence is presented that the gene can be targeted for deletion indicating a non-essential role for blood stage growth/multiplication.
Additional information
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