Topoisomerase II-oligonucleotide complexes in non-meiotic yeast cells. a, Extracts were prepared from vegetatively growing yeast strains carrying topoisomerase II with (TOP2-HA3) or without (TOP2) an epitope tag. Samples were immunoprecipitated with anti-HA antibody and labelled with TdT. b, Comparison of electrophoretic mobilities of free and oligonucleotide-associated Top2-HA3. Immunoprecipitated Top2-HA3 was labelled with TdT, separated on 5% SDS-PAGE, and transferred to PVDF membrane. Autoradiograph and anti-HA western of the membrane are shown. c, Formation of Top2-oligonucleotide complexes in nuclease-defective mutants. Arrow, Top2-HA3-specific band.