title: The DNA sequence specificity of bleomycin cleavage in telomeric sequences in human cells.
abstract: Bleomycin is an antibiotic drug that is widely used in cancer chemotherapy. Telomeres are located at the ends of chromosomes and comprise the tandemly repeated DNA sequence (GGGTTA)(                   n                 ) in humans. Since bleomycin cleaves DNA at 5'-GT dinucleotide sequences, telomeres are expected to be a major target for bleomycin cleavage. In this work, we determined the DNA sequence specificity of bleomycin cleavage in telomeric sequences in human cells. This was accomplished using a linear amplification procedure, a fluorescently labelled oligonucleotide primer and capillary gel electrophoresis with laser-induced fluorescence detection. This represents the first occasion that the DNA sequence specificity of bleomycin cleavage in telomeric DNA sequences in human cells has been reported. The bleomycin DNA sequence selectivity was mainly at 5'-GT dinucleotides, with lesser amounts at 5'-GG dinucleotides. The cellular bleomycin telomeric DNA damage was also compared with bleomycin telomeric damage in purified human genomic DNA and was found to be very similar. The implications of these results for the understanding of bleomycin's mechanism of action in human cells are discussed.
authors.affiliation: School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.
authors.forename: Hanh T Q
authors.initials: HT
authors.lastname: Nguyen
authors.forename: Vincent
authors.initials: V
authors.lastname: Murray
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D001483:Base Sequence / Q000187:drug effects*; D001761:Bleomycin / Q000494:pharmacology*; D006367:HeLa Cells; D006801:Humans; D013379:Substrate Specificity; D020080:Tandem Repeat Sequences / Q000187:drug effects / Q000235:genetics; D016615:Telomere / Q000187:drug effects*
chemical_list: D000970:Antineoplastic Agents; D001761:Bleomycin