Mutant/mutation
The mutant expresses a C-terminal mCherry-tagged version of ABCG2

Protein (function)
In different Plasmodium parasites 14-16 ABC-transporter genes have been identified (16 in P. falciparum, 14 in P. berghei) with one member of the ABCG subfamily (ABCG2).

Expression of PfgABCG2 of P. falciparum in the sexual stages is restricted to female gametocytes, where it localizes to a distinct single spherical structure near the apical end, termed the gametocyte-specific spot. Deletion of gABCG2 in P. falciparum results in an increase in gametocytes of both sexes and reduced levels of cholesteryl esters, diacylglycerol and triacylglycerol. These neutral lipids play a role in storing energy and building blocks for metabolic synthesis. It was, therefore, proposed that P. falciparum gABCG2 might play a role in accumulation of neutral lipids, and the gametocyte-specific spot represents a modified lipid body serving as a storage compartment for lipids that are required for parasite development in the mosquito. Access to neutral lipids in the mosquito is restricted due to the inability of both the parasite and the host to synthesize some of the neutral lipids such as cholesterol and due to competition. For instance, triacylglycerols are rapidly absorbed in the midgut, since they are a significant component for egg production. Based on sequence homology, our hypothesis was that P. berghei gABCG2 is a functional homolog of P. falciparum gABCG2. It was previously shown that P. berghei gABCG2 is dispensable for progression through the entire life cycle, in good agreement with the data on blood infection from P. falciparum

Phenotype
PbgABCG2-mCherry parasites revealed very low expression in trophozoites and a bright, distinct expression in female gametocytes. PbgABCG2 displays localization to internal structures and a uniform, circumferential localization, consistent with a localization to the parasite plasma membrane.
PbgABCG2-mCherry  continued to be expressed in zygotes and ookinetes. In ookinetes PbgABCG2 is detected predominantly at the parasite plasma membrane.

Additional information
From the abstract:
'Here, we present detailed functional profiling of the female gametocyte-specific ATP-binding cassette transporter gABCG2 in the murine parasite P. berghei and compare our findings with data from the orthologous gene in the human parasite Plasmodium falciparum. We show that P. berghei gABCG2 is female-specific and continues to be expressed in zygotes and ookinetes. In contrast to a distinct localization to Iipid-rich gametocyte-specific spots as observed in P. falciparum, the murine malaria parasite homolog is found at the parasite plasma membrane. P. berghei lacking gABCG2 displays fast asexual blood-stage replication and increased proportions of female gametocytes, consistent with the corresponding P. falciparum knock-out phenotype.'
Cross-species replacement of gABCG2 in either the murine (RMgm-4836) or the human parasite did not restore normal growth rates, demonstrating the lack of successful complementation.

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