Project description:The genomic DNAs of strains 263 of L. infantum and five derived independent resistant mutants to 5-fluorouracil were used in comparative genomic hybridizations to reveal the deletion and/or amplification events occured by drug resistance mechanisms. The human protozoan parasites Leishmania are prototrophic for pyrimidines and de novo pyrimidine biosynthesis is necessary for their growth. 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 amplification and deletion events as well as point mutations in metabolic genes involved in either the uridine salvage, folate or dTMP biosynthesis pathways. In particular, a dhfr-ts containing amplicon was observed in two mutants and a deletion of part of chromosome 10 was detected in one mutant. Point mutations in uridine phosphorybosyl transferase (UPRT), thymidine kinase (TK) and uridine phosphorylase (UP) were also discovered. Transfection experiments confirmed that these molecular alterations were responsible for the 5-FU resistance phenotype. Transport studies revealed that one resistant mutant was defective for uracil and 5-FU import although the identity of the transporter remains elusive. This study provided further insights in pyrimidine metabolism in Leishmania and confirmed that multiple mutations can co-exist in a cell to lead to resistance. Each independent resistant mutant to 5-fluorouracil was hybridizated with the wild-type L. infantum 263 to 10 microarrays, each with three biological replicates (independent cultures).
Project description:The genomic DNAs of strains 263 of L. infantum and five derived independent resistant mutants to 5-fluorouracil were used in comparative genomic hybridizations to reveal the deletion and/or amplification events occured by drug resistance mechanisms. The human protozoan parasites Leishmania are prototrophic for pyrimidines and de novo pyrimidine biosynthesis is necessary for their growth. 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 amplification and deletion events as well as point mutations in metabolic genes involved in either the uridine salvage, folate or dTMP biosynthesis pathways. In particular, a dhfr-ts containing amplicon was observed in two mutants and a deletion of part of chromosome 10 was detected in one mutant. Point mutations in uridine phosphorybosyl transferase (UPRT), thymidine kinase (TK) and uridine phosphorylase (UP) were also discovered. Transfection experiments confirmed that these molecular alterations were responsible for the 5-FU resistance phenotype. Transport studies revealed that one resistant mutant was defective for uracil and 5-FU import although the identity of the transporter remains elusive. This study provided further insights in pyrimidine metabolism in Leishmania and confirmed that multiple mutations can co-exist in a cell to lead to resistance.
Project description:We explored the potential reprogramming of Leishmania infantum proteome during its stationary phase after an initial, single-dose exposure to EVs released by drug-resistant parasites
Project description:The genomic DNAs of strains JPCM5 and 263 of L. infantum, strains LV39 and Friedlin of L. major and strains Parrot-TarII and S125 of L. tarentolae were used in comparative genomic hybridizations to reveal the intra-species and inter-species gene content, and to validate L. tarentolae Parrot-TarII genome sequencing results. Leishmania (Sauroleishmania) tarentolae was first isolated in the lizard Tarentola mauritanica. This species is not known to be pathogenic to humans but is often used as a model organism for molecular analyses or protein overproduction. The Leishmania tarentolae Parrot-TarII strain genome sequence was resolved by high-throughput sequencing technologies. The L. tarentolae genome was first assembled de novo and then aligned against the reference L. major Friedlin genome to facilitate contig positioning and annotation, providing a 23-fold coverage of the genome. This is the first non-pathogenic to humans kinetoplastid protozoan genome to be described, and it provides an opportunity for comparison with the completed genomes of the pathogenic Leishmania species. A high synteny was observed in de novo assembled contigs between all sequenced Leishmania species. A number of limited chromosomal regions diverged between L. tarentolae and L. infantum, while remaining syntenic with L. major. Globally, over 90% of the L. tarentolae gene content was shared with the other Leishmania species. There were 250 L. major genes absent from L. tarentolae, and interestingly these missing genes were primarily expressed in the intracellular amastigote stage of the pathogenic parasites. This implies that L. tarentolae may have impaired ability to survive as an intracellular parasite. In contrast to other Leishmania genomes, two gene families were expanded in L. tarentolae, namely the leishmanolysin (GP63) and a gene related to the promastigote surface antigen (PSA31C). Overall, L. tarentolae appears to have a gene content more adapted to the insect stage rather than the mammalian one. This may partly explain its inability to replicate within mammalian macrophages and its suspected preferred life style as promastigote in the lizards. Six strains of three Leishmania species were hybridizated to 12 microarrays, each with four biological replicates (independent cultures). Supplementary file: Represents final results obtained after statistical analysis of all replicates.