Modification of kinetoplast DNA minicircle composition in pentamidine-resistant Leishmania.
Pentamidine, an antiprotozoal drug, was shown to have various cellular and molecular targets depending on the organism. In Leishmania, ultrastructural modifications of kinetoplast and mitochondria have been observed but no data is available on cellular and molecular events involved in development of pentamidine-resistance. The absence of modification of minicircle DNA in pentamidine treated L. donovani and L. amazonensis promastigotes suggested that topoisomerase II activity is not a target. This result was confirmed by quantitation of the enzyme by immunodetection. Southern blot experiments indicated that the kDNA network was altered in resistant clones. Molecular cloning and sequence analysis of kDNA minicircles showed transkinetoplastidy hitherto reported only for arsenite- and tunicamycin-resistant Leishmania. Comparison of wild-type and resistant sequences showed only 32-51% homology. The AT-rich regions, known as binding sites, of the drug occurred less frequently in the resistant clones and their locations were different. These minicircle sequence modifications leading to decreased binding sites for the drug might contribute to pentamidine-resistance in Leishmania.
Institut de Chimie des Substances Naturelles, C.N.R.S., Gif-sur-Yvette, France. mab6s@udcf.gla.ac.uk
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Basselin
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Badet-Denisot
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Robert-Gero
D000818:Animals; D000981:Antiprotozoal Agents / Q000378:metabolism / Q000494:pharmacology*; D001483:Base Sequence; D001665:Binding Sites; D004250:DNA Topoisomerases, Type II / Q000378:metabolism*; D018105:DNA, Kinetoplast / Q000737:chemistry*; D004351:Drug Resistance; D007893:Leishmania donovani / Q000187:drug effects* / Q000235:genetics; D007894:Leishmania mexicana / Q000187:drug effects* / Q000235:genetics; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010419:Pentamidine / Q000378:metabolism / Q000494:pharmacology*; D019105:Random Amplified Polymorphic DNA Technique; D012091:Repetitive Sequences, Nucleic Acid; D017422:Sequence Analysis, DNA
D000981:Antiprotozoal Agents; D018105:DNA, Kinetoplast; D010419:Pentamidine; D004250:DNA Topoisomerases, Type II