title: A novel marker, ARM58, confers antimony resistance to Leishmania spp.
abstract: Protozoa of the Leishmania genus cause a variety of disease forms that rank at the top of the list of neglected tropical diseases. Anti-leishmanial drugs based on pentavalent antimony have been the mainstay of therapy for over 60 years and resistance against them is increasingly encountered in the field. The biochemical basis for this is poorly understood and likely diverse. No stringent correlation between genetic markers and antimony resistance has so far been shown, prompting us to use a functional cloning approach to identify markers of resistance. Using gene libraries derived from drug-resistant and drug-sensitive Leishmania braziliensis clinical isolates in a functional cloning strategy, we repeatedly selected one gene locus located on chromosome 20 whose amplification confers increased antimony (III) resistance in vitro to an otherwise sensitive L. braziliensis clone. The gene responsible for the effect encodes a previously hypothetical protein that we dubbed LbrARM58. It comprises four repeats of a domain of unknown function, DUF1935, one of them harbouring a potential trans-membrane domain. The gene is so far unique to the Leishmania genus, while a structurally related gene without antimony resistance functionality is also found in Trypanosoma spp. Overexpression of LbrARM58 also confers antimony resistance to promastigotes and intracellular amastigotes of the related species Leishmania infantum, indicating a conserved function in Old World and New World Leishmania species. Our results also show that in spite of their RNAi system, L. braziliensis promastigotes can serve as acceptor cells for episomally propagated cosmid libraries, at least for the initial stages of functional cloning efforts.
authors.affiliation: Bernhard Nocht Institute for Tropical Medicine, D20359 Hamburg, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Nühs
authors.affiliation: Bernhard Nocht Institute for Tropical Medicine, D20359 Hamburg, Germany.
authors.forename: Carola
authors.initials: C
authors.lastname: Schäfer
authors.affiliation: Bernhard Nocht Institute for Tropical Medicine, D20359 Hamburg, Germany.
authors.forename: Dorothea
authors.initials: D
authors.lastname: Zander
authors.affiliation: Bernhard Nocht Institute for Tropical Medicine, D20359 Hamburg, Germany.
authors.forename: Leona
authors.initials: L
authors.lastname: Trübe
authors.affiliation: Bernhard Nocht Institute for Tropical Medicine, D20359 Hamburg, Germany.
authors.forename: Paloma
authors.initials: P
authors.lastname: Tejera Nevado
authors.affiliation: Bernhard Nocht Institute for Tropical Medicine, D20359 Hamburg, Germany.
authors.forename: Sonja
authors.initials: S
authors.lastname: Schmidt
authors.affiliation: Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors.forename: Jorge
authors.initials: J
authors.lastname: Arevalo
authors.affiliation: Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Adaui
authors.affiliation: Department of Biomedical Sciences, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Antwerp, Belgium.
authors.forename: Louis
authors.initials: L
authors.lastname: Maes
authors.affiliation: Instituut voor Tropische Geneeskunde, Antwerp, Belgium ; Department of Biomedical Sciences, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Antwerp, Belgium.
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Dujardin
authors.affiliation: Bernhard Nocht Institute for Tropical Medicine, D20359 Hamburg, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Clos
keywords: Antimony; Leishmania braziliensis; Resistance