title: Efficient repair of bleomycin-induced double-strand breaks in barley ribosomal genes.
abstract: Ability of barley ribosomal genes to cope with damage produced in vivo by the radiomimetic agent bleomycin was investigated. Repair kinetics of bleomycin-induced double-strand breaks in ribosomal and total genomic DNA was compared. Induction and repair of double-strand breaks in defined regions of the ribosomal genes was also analyzed. Preferential sensitivity of barley linker DNA towards bleomycin treatment in vivo was established. Relatively higher yield of initially induced double-strand breaks in genomic DNA in comparison to ribosomal DNA was also found. Fragments containing intergenic spacers of barley rRNA genes displayed higher sensitivity to bleomycin than the coding sequences. No heterogeneity in the repair of DSB between transcribed and non-transcribed regions of ribosomal genes was detected. Data indicate that DSB repair in barley rDNA, although more efficient than in genomic DNA, does not correlate with the activity of nucleolus organizer regions.
authors.affiliation: Department of Molecular Genetics, Institute of Genetics, Acad D Kostoff, BAS, Sofia, Bulgaria.
authors.forename: Vasilissa
authors.initials: V
authors.lastname: Manova
authors.forename: Kostadin
authors.initials: K
authors.lastname: Gecheff
authors.forename: Lubomir
authors.initials: L
authors.lastname: Stoilov
mesh_terms: D001761:Bleomycin / Q000494:pharmacology*; D015139:Blotting, Southern; D053903:DNA Breaks, Double-Stranded / Q000187:drug effects*; D053904:DNA Breaks, Single-Stranded; D004249:DNA Damage; D004260:DNA Repair / Q000187:drug effects*; D018744:DNA, Plant / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics*; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D001467:Hordeum / Q000187:drug effects / Q000235:genetics*; D018517:Plant Roots / Q000166:cytology / Q000187:drug effects / Q000235:genetics; D013997:Time Factors
chemical_list: D018744:DNA, Plant; D004275:DNA, Ribosomal; D021903:DNA, Ribosomal Spacer; D001761:Bleomycin