TY - JOUR
T1 - Phenotypic characterization of a glucose transporter null mutant in Leishmania mexicana
AU - Rodriguez-Contreras, Dayana
AU - Feng, Xiuhong
AU - Keeney, Kristie M.
AU - Bouwer, H. G.Archie
AU - Landfear, Scott M.
N1 - Funding Information:
This work was supported by NIH grant AI25920 to SML, a VA Merit Review award and NIH grant U01 AI056446 to HGB, and by a postdoctoral fellowship from the American Heart Association to DR-C. We would like to thank Dr. Natalia Akopyants and Dr. Steven Beverley for sharing with us the method for cell volume determination, and Suzanne Brandt for providing murine marrow-derived macrophages.
PY - 2007/5
Y1 - 2007/5
N2 - Glucose is a major source of energy and carbon in promastigotes of Leishmania mexicana, and its uptake is mediated by three glucose transporters whose genes are encoded within a single cluster. A null mutant in which the glucose transporter gene cluster was deleted by homologous gene replacement was generated previously and shown to grow more slowly than wild type promastigotes but not to be viable as amastigotes in primary tissue culture macrophages or in axenic culture. Further phenotypic characterization demonstrates that the null mutant is unable to import glucose, mannose, fructose, or galactose and that each of the three glucose transporter isoforms, LmGT1, LmGT2, and LmGT3, is capable of transporting each of these hexoses. Complementation of the null mutant with each isoform is able to restore growth in each of the four hexoses to wild type levels. Null mutant promastigotes are reduced in size to about 2/3 the volume of wild type parasites. In addition, the null mutants are significantly more sensitive to oxidative stress than their wild type counterparts. These results underscore the importance of glucose transporters in the parasite life cycle and suggest reasons for their non-viability in the disease-causing amastigote stage.
AB - Glucose is a major source of energy and carbon in promastigotes of Leishmania mexicana, and its uptake is mediated by three glucose transporters whose genes are encoded within a single cluster. A null mutant in which the glucose transporter gene cluster was deleted by homologous gene replacement was generated previously and shown to grow more slowly than wild type promastigotes but not to be viable as amastigotes in primary tissue culture macrophages or in axenic culture. Further phenotypic characterization demonstrates that the null mutant is unable to import glucose, mannose, fructose, or galactose and that each of the three glucose transporter isoforms, LmGT1, LmGT2, and LmGT3, is capable of transporting each of these hexoses. Complementation of the null mutant with each isoform is able to restore growth in each of the four hexoses to wild type levels. Null mutant promastigotes are reduced in size to about 2/3 the volume of wild type parasites. In addition, the null mutants are significantly more sensitive to oxidative stress than their wild type counterparts. These results underscore the importance of glucose transporters in the parasite life cycle and suggest reasons for their non-viability in the disease-causing amastigote stage.
KW - Glucose transporters
KW - Hexose transport
KW - Leishmania mexicana
KW - Null mutant
KW - Oxidative stress
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U2 - 10.1016/j.molbiopara.2007.01.010
DO - 10.1016/j.molbiopara.2007.01.010
M3 - Article
C2 - 17306380
AN - SCOPUS:34047103887
SN - 0166-6851
VL - 153
SP - 9
EP - 18
JO - Molecular and Biochemical Parasitology
JF - Molecular and Biochemical Parasitology
IS - 1
ER -