Tunicamycin-resistant variants from five species of Leishmania contain amplified DNA in extrachromosomal circles of different sizes with a transcriptionally active homologous region
| Autor: | Yan Peng, Ronnie Pithawalla, Siegfried Detke, Ken Katakura, Kwang-Poo Chang |
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| Rok vydání: | 1991 |
| Předmět: |
Transcription
Genetic Restriction Mapping Drug Resistance Gene Expression Transferases (Other Substituted Phosphate Groups) Biology chemistry.chemical_compound Restriction map Species Specificity Extrachromosomal DNA Sequence Homology Nucleic Acid Gene duplication Animals Molecular Biology Gene Genetics Leishmania Tunicamycin Phosphotransferases Gene Amplification Amplicon DNA Protozoan biology.organism_classification Blotting Northern Molecular biology chemistry Parasitology DNA Circular DNA |
| Zdroj: | Molecular and biochemical parasitology. 44(2) |
| ISSN: | 0166-6851 |
| Popis: | Twelve independent variants were selected from five species of Leishmania for resistance to tunicamycin by exposure of cultured promastigotes to increasing concentrations of this antibiotic, an inhibitor of the microsomal N-acetylglucosamine-1-phosphate transferase in the dolichol pathway of N-glycosylation. All variants obtained from all species, as found previously with Leishmania amazonensis, contain amplified chromosomal DNA exclusively as extrachromosomal circles. These circular amplicons hybridize with amplified DNAs cloned previously from tunicamycin-resistant Leishmania amazonensis, but not with those from Leishmania resistant to other drugs. The amplicons from tunicamycin-resistant cells vary with different species in size from 30 to 70 kb, but all share a homologous region of 20 kb. Multiple independent transcripts are overexpressed from this region. Elevation of the microsomal glycosyltransferase activity is demonstrated in these variants from representative species. The results thus provide further evidence that this enzyme is overexpressed due to amplification of the gene in these cells. The consistent observation of this event in all cases studied also suggests that this is the predominant, if not the only mechanism of tunicamycin resistance in Leishmania. |
| Databáze: | OpenAIRE |
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