A Telomeric Cluster of Antimony Resistance Genes on Chromosome 34 of Leishmania infantum.
The mechanisms underlying the drug resistance of Leishmania spp. are manifold and not completely identified. Apart from the highly conserved multidrug resistance gene family known from higher eukaryotes, Leishmania spp. also possess genus-specific resistance marker genes. One of them, ARM58, was first identified in Leishmania braziliensis using a functional cloning approach, and its domain structure was characterized in L. infantum Here we report that L. infantum ARM58 is part of a gene cluster at the telomeric end of chromosome 34 also comprising the neighboring genes ARM56 and HSP23. We show that overexpression of all three genes can confer antimony resistance to intracellular amastigotes. Upon overexpression in L. donovani, ARM58 and ARM56 are secreted via exosomes, suggesting a scavenger/secretion mechanism of action. Using a combination of functional cloning and next-generation sequencing, we found that the gene cluster was selected only under antimonyl tartrate challenge and weakly under Cu(2+) challenge but not under sodium arsenite, Cd(2+), or miltefosine challenge. The selective advantage is less pronounced in intracellular amastigotes treated with the sodium stibogluconate, possibly due to the known macrophage-stimulatory activity of this drug, against which these resistance markers may not be active. Our data point to the specificity of these three genes for antimony resistance.
Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.
Paloma
P
Tejera Nevado
Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.
Eugenia
E
Bifeld
Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.
Katharina
K
Höhn
Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany clos@bnitm.de.
Joachim
J
Clos
D000965:Antimony / Q000494:pharmacology*; D000967:Antimony Sodium Gluconate / Q000494:pharmacology; D000981:Antiprotozoal Agents / Q000494:pharmacology*; D002104:Cadmium / Q000494:pharmacology; D003001:Cloning, Molecular; D003300:Copper / Q000494:pharmacology; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004351:Drug Resistance / Q000235:genetics*; D055354:Exosomes / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D015870:Gene Expression; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D059014:High-Throughput Nucleotide Sequencing; D018314:Leishmania infantum / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D008018:Life Cycle Stages / Q000187:drug effects / Q000235:genetics; D005810:Multigene Family; D010767:Phosphorylcholine / Q000031:analogs & derivatives / Q000494:pharmacology; D015800:Protozoan Proteins / Q000235:genetics* / Q000378:metabolism; D016615:Telomere / Q000737:chemistry* / Q000378:metabolism
D000981:Antiprotozoal Agents; D029721:Drosophila Proteins; D006360:Heat-Shock Proteins; C105998:Hsp23 protein, Drosophila; D015800:Protozoan Proteins; D002104:Cadmium; D010767:Phosphorylcholine; C039128:miltefosine; D003300:Copper; D000965:Antimony; D000967:Antimony Sodium Gluconate