| Liver stage | Immunofluorescence microscopy of HepG2 cells infected with myc-tagged berghepain-1 parasites showed low levels of berghepain-1-myc expression at 24 h post infection, which increased at 36 h in late hepatic trophozoite stages. At 48 h post infection, berghepain-1-myc surrounded the individual nuclei and this perinuclear pattern was still present at 56 h. At 33 h post infection, berghepain-1-myc was also found in larger sub-compartments of the parasites, which co-localized with the staining of the ER marker BiP. Berghepain-1-myc did not co-localize with cytosolic marker HSP70, or the membrane marker MSP1 or with CSP. No expression was observed in merozoites of merosomes. |
| Additional remarks phenotype | Mutant/mutation
The mutant expresses a C-terminal triple c-myc-tagged version of BP1
Protein (function)
P. falciparum expresses four cysteine proteases namely, falcipain-1 (FP-1), falcipain-2 and -2' (FP-2A and FP-2B) and falcipain-3 (FP-3) at asexual blood stages of the parasite. These proteases perform multiple functions such as hemoglobin hydrolysis, erythrocyte rupture and erythrocyte invasion and differ in their timing of expression. Falcipain-1 is active at the invasive merozoite stage while falcipain-2/-2' and -3 are expressed mainly at early and late trophozoite stages respectively.
Both P. falciparum and P. berghei have an papain-like cysteine protease encoded by a syntenic gene (falcipain 1, FP1, PF3D7_1458000 and berghepain 1, BP1, PBANKA_132170). Evidence has been presented that this protease is located (and active) in the (apical end) of merozoites and not in the digestive vacuole, suggesting that it has no role in hemoglobin digestion.
P. berghe has an additional papain-like cysteine protease, Berghepain-2 (BP2), which is equivalent to the three P. falciparum digestive vacuole falcipains (papain-like cysteine endoproteases), FP-2 (FP2a, PF3D7_1115700; FP2b, PF3D7_1115300) and -3 (PF3D7_1115400). The gene encoding BP2 has a syntenic location to the three falcipain genes of P. falciparum and also the the single copy vivapain-2 of P. Vivax (PVX_086040).
Phenotype
Berghepain-1-myc is expressed in early schizonts and the staining localizes to the individual merozoites in segmented mature schizonts.
Immunofluorescence microscopy of HepG2 cells infected with myc-tagged berghepain-1 parasites showed low levels of berghepain-1-myc expression at 24 h post infection, which increased at 36 h in late hepatic trophozoite stages. At 48 h post infection, berghepain-1-myc surrounded the individual nuclei and this perinuclear pattern was still present at 56 h. At 33 h post infection, berghepain-1-myc was also found in larger sub-compartments of the parasites, which co-localized with the staining of the ER marker BiP. Berghepain-1-myc did not co-localize with cytosolic marker HSP70, or the membrane marker MSP1 or with CSP. No expression was observed in merozoites of merosomes.
Additional information
Other mutants
See PF3D7_145800 |
*RMgm-4362
