Mutant/mutation
The mutant lacks expression of Novel Putative Transporter, NPT1. See also RMgm-626 for a more detailed analysis of a P. berghei mutant lacking NPT1.

Protein (function)
The P. falciparum homolog of P. berghei NPT1 has been reported to belong to an uncharacterized family of 5 novel putative transporters (NPTs) presenting some features of the Major Facilitating Superfamily (MFS) (Martin et al., 2005, Genome Biol.).  Plasmodium NPT1 proteins are predicted to contain 12 transmembrane domains. Transcription/expression of the npt1 gene has been shown for blood-, mosquito- and liver stages with increased transcript levels in liver stages.

Phenotype
See also RMgm-626 for a more detailed analysis of a P. berghei mutant lacking NPT1. Phenotype analyses of mutant RMgm-626 showed the following:  a strongly reduced gametocyte production. The few gametocytes present show an aberrant morphology (as shown by both ligh-microscopy and transmission electron microscopy analyses). These aberrant forms are unable to fertilize and to produce ookinetes.

Analysis of ΔPbnpt1 showed the following: Evidence is provided that blood stages of the mutant show reduced uptake of cationic amino acids (Arginine, Lysine). Evidence is presented that NPT1 is a cationic amino transporter in both T. gondii and Plasmodium.

Additional information
From the Abstract: 'Apicomplexans are obligate intracellular parasites that scavenge essential nutrients from their hosts via transporter proteins on their plasma membrane. The identities of the transporters that mediate amino acid uptake into apicomplexans are unknown. Here we demonstrate that members of an apicomplexan-specific protein family—the Novel Putative Transporters (NPTs)—play key roles in the uptake of cationic amino acids. We show that an NPT from Toxoplasma gondii (TgNPT1) is a selective arginine transporter that is essential for parasite survival and virulence. We also demonstrate that a homologue of TgNPT1 from the malaria parasite Plasmodium berghei (PbNPT1), shown previously to be essential for the sexual gametocyte stage of the parasite, is a cationic amino acid transporter. This reveals a role for cationic amino acid scavenging in gametocyte biology.'

Other mutants
see NPT1