title: Gene amplification and point mutations in pyrimidine metabolic genes in 5-fluorouracil resistant Leishmania infantum.
abstract: BACKGROUND
  The human protozoan parasites Leishmania are prototrophic for pyrimidines with the ability of both de novo biosynthesis and uptake of pyrimidines.
  
  
  RESULTS
  Five independent L. infantum mutants were selected for resistance to the pyrimidine analogue 5-fluorouracil (5-FU) in the hope to better understand the metabolism of pyrimidine in Leishmania. Analysis of the 5-FU mutants by comparative genomic hybridization and whole genome sequencing revealed in selected mutants the amplification of DHFR-TS and a deletion of part of chromosome 10. Point mutations in uracil phosphorybosyl transferase (UPRT), thymidine kinase (TK) and uridine phosphorylase (UP) were also observed in three individual resistant mutants. Transfection experiments confirmed that these point mutations were responsible for 5-FU resistance. Transport studies revealed that one resistant mutant was defective for uracil and 5-FU import.
  
  
  CONCLUSIONS
  This study provided further insights in pyrimidine metabolism in Leishmania and confirmed that multiple mutations can co-exist and lead to resistance in Leishmania.
authors.affiliation: Centre de recherche en Infectiologie du CHU de Québec and Département de Microbiologie, Infectiologie et Immunologie, Université Laval, Québec City, Québec, Canada.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Ritt
authors.forename: Frédéric
authors.initials: F
authors.lastname: Raymond
authors.forename: Philippe
authors.initials: P
authors.lastname: Leprohon
authors.forename: Danielle
authors.initials: D
authors.lastname: Légaré
authors.forename: Jacques
authors.initials: J
authors.lastname: Corbeil
authors.forename: Marc
authors.initials: M
authors.lastname: Ouellette
mesh_terms: D000981:Antiprotozoal Agents / Q000494:pharmacology*; D053898:Biosynthetic Pathways / Q000235:genetics; D055028:Comparative Genomic Hybridization; D004252:DNA Mutational Analysis; D004351:Drug Resistance; D005472:Fluorouracil / Q000494:pharmacology*; D018314:Leishmania infantum / Q000187:drug effects* / Q000235:genetics; D009154:Mutation; D015800:Protozoan Proteins / Q000235:genetics*; D011743:Pyrimidines / Q000096:biosynthesis*; D017422:Sequence Analysis, DNA; D014162:Transfection
chemical_list: D000981:Antiprotozoal Agents; D015800:Protozoan Proteins; D011743:Pyrimidines; C030986:pyrimidine; D005472:Fluorouracil