TY - JOUR
T1 - Genetic evidence for the essential role of PfNT1 in the transport and utilization of xanthine, guanine, guanosine and adenine by Plasmodium falciparum
AU - Bissati, Kamal El
AU - Downie, Megan J.
AU - Kim, Seong Kyoun
AU - Horowitz, Michael
AU - Carter, Nicola
AU - Ullman, Buddy
AU - Mamoun, Choukri Ben
N1 - Funding Information:
We are grateful to Harriet Zawistowski (General Clinical Research Center, University of Connecticut Health Center) for her technical help. This research was supported by grant AI51507 from the National Institute of Allergy and Infectious Disease (to C.B.M. and B.U.); grant PR033005 from the Department of Defense to C.B.M. and the Burroughs Wellcome fund (to C.B.M.). C.B.M. is a recipient of the Burroughs Wellcome Award (1006267), Investigators of Pathogenesis of Infectious Diseases. This work was also supported in part by National Institutes of Health General Clinical Research Center Grant M01RR06192 (to the University of Connecticut Health Center).
PY - 2008/10
Y1 - 2008/10
N2 - The malaria parasite, Plasmodium falciparum, is unable to synthesize the purine ring de novo and is therefore wholly dependent upon purine salvage from the host for survival. Previous studies have indicated that a P. falciparum strain in which the purine transporter PfNT1 had been disrupted was unable to grow on physiological concentrations of adenosine, inosine and hypoxanthine. We have now used an episomally complemented pfnt1Δ knockout parasite strain to confirm genetically the functional role of PfNT1 in P. falciparum purine uptake and utilization. Episomal complementation by PfNT1 restored the ability of pfnt1Δ parasites to transport and utilize adenosine, inosine and hypoxanthine as purine sources. The ability of wild-type and pfnt1Δ knockout parasites to transport and utilize the other physiologically relevant purines adenine, guanine, guanosine and xanthine was also examined. Unlike wild-type and complemented P. falciparum parasites, pfnt1Δ parasites could not proliferate on guanine, guanosine or xanthine as purine sources, and no significant transport of these substrates could be detected in isolated parasites. Interestingly, whereas isolated pfnt1Δ parasites were still capable of adenine transport, these parasites grew only when adenine was provided at high, non-physiological concentrations. Taken together these results demonstrate that, in addition to hypoxanthine, inosine and adenosine, PfNT1 is essential for the transport and utilization of xanthine, guanine and guanosine.
AB - The malaria parasite, Plasmodium falciparum, is unable to synthesize the purine ring de novo and is therefore wholly dependent upon purine salvage from the host for survival. Previous studies have indicated that a P. falciparum strain in which the purine transporter PfNT1 had been disrupted was unable to grow on physiological concentrations of adenosine, inosine and hypoxanthine. We have now used an episomally complemented pfnt1Δ knockout parasite strain to confirm genetically the functional role of PfNT1 in P. falciparum purine uptake and utilization. Episomal complementation by PfNT1 restored the ability of pfnt1Δ parasites to transport and utilize adenosine, inosine and hypoxanthine as purine sources. The ability of wild-type and pfnt1Δ knockout parasites to transport and utilize the other physiologically relevant purines adenine, guanine, guanosine and xanthine was also examined. Unlike wild-type and complemented P. falciparum parasites, pfnt1Δ parasites could not proliferate on guanine, guanosine or xanthine as purine sources, and no significant transport of these substrates could be detected in isolated parasites. Interestingly, whereas isolated pfnt1Δ parasites were still capable of adenine transport, these parasites grew only when adenine was provided at high, non-physiological concentrations. Taken together these results demonstrate that, in addition to hypoxanthine, inosine and adenosine, PfNT1 is essential for the transport and utilization of xanthine, guanine and guanosine.
KW - Malaria
KW - PfNT1
KW - Plasmodium falciparum
KW - Purine
KW - Transport
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U2 - 10.1016/j.molbiopara.2008.06.012
DO - 10.1016/j.molbiopara.2008.06.012
M3 - Article
C2 - 18639591
AN - SCOPUS:49049111269
SN - 0166-6851
VL - 161
SP - 130
EP - 139
JO - Molecular and Biochemical Parasitology
JF - Molecular and Biochemical Parasitology
IS - 2
ER -