Differential regulation of two distinct families of glucose transporter genes in Trypanosoma brucei.
A tandemly arranged multigene family encoding putative hexose transporters in Trypanosoma brucei has been characterized. It is composed of two 80% homologous groups of genes called THT1 (six copies) and THT2 (five copies). When Xenopus oocytes are microinjected with in vitro-transcribed RNA from a THT1 gene, they express a glucose transporter with properties similar to those of the trypanosome bloodstream-form protein(s). This THT1-encoded transport system for glucose differs from the human erythrocyte-type glucose transporter by its moderate sensitivity to cytochalasin B and its capacity to transport D-fructose. These properties suggest that the trypanosomal transporter may be a good target for antitrypanosomal drugs. mRNA analysis revealed that expression of these genes was life cycle stage dependent. Bloodstream forms express 40-fold more THT1 than THT2. In contrast, procyclic trypanosomes express no detectable THT1 but demonstrate glucose-dependent expression of THT2.
Bringaud
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Laboratoire Immunologie et Parasitologie Moléculaire, Université Bordeaux II, France.
Baltz
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T
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016054:DNA, Protozoan; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins / Q000235:genetics*; D005810:Multigene Family; D015800:Protozoan Proteins / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D014346:Trypanosoma brucei brucei / Q000235:genetics*
D016054:DNA, Protozoan; D009004:Monosaccharide Transport Proteins; D015800:Protozoan Proteins; C079374:THT1 protein, Trypanosoma brucei; C079375:THT2 protein, Trypanosoma brucei