Molecular and functional characterization of the first nucleobase transporter gene from African trypanosomes

Cristina Henriques, Marco A. Sanchez, Rob Tryon, Scott M. Landfear

Research output: Contribution to journalArticle

25 Scopus citations

Abstract

African trypanosomes are unable to synthesize purines and depend upon purine nucleoside and nucleobase transporters to salvage these compounds from their hosts. To understand the crucial role of purine salvage in the survival of these parasites, a central objective is to identify and characterize all of the purine permeases that mediate uptake of these essential nutrients. We have cloned and functionally expressed in a purine nucleobase transport deficient strain of Saccharomyces cerevisiae a novel nucleobase transporter gene, TbNT8.1, from Trypanosoma brucei. The permease encoded by this gene mediates the uptake of hypoxanthine, adenine, guanine, and xanthine with Kms in the low micromolar range. The TbNT8.1 protein is a member of the equilibrative nucleoside transporter (ENT) family of permeases that occur in organisms as diverse as protozoa and mammals. TbNT8.1 is distinct from other ENT permeases that have been identified in trypanosomes in utilizing multiple purine nucleobases, rather than purine nucleosides, as substrates and is hence the first bona fide nucleobase permease identified in these parasites. Furthermore, unlike the mRNAs for other purine transporters, TbNT8.1 mRNA is significantly more abundant in insect stage procyclic forms than in mammalian stage bloodstream forms, and the TbNT8.1 permease thus may represent a major route for purine nucleobase uptake in procyclic trypanosomes.

Original languageEnglish (US)
Pages (from-to)101-110
Number of pages10
JournalMolecular and Biochemical Parasitology
Volume130
Issue number2
DOIs
StatePublished - Aug 31 2003

Keywords

  • African trypanosomes
  • Heterologous expression in yeast
  • Nucleobase transporter
  • Purine salvage

ASJC Scopus subject areas

  • Parasitology
  • Molecular Biology

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