Biopolym. Cell. 1993; 9(6):52-59.
Structure and Function of Biopolymers
Fractionation of eukaryotic DNA by pulsed field gel electrophoresis. The peculiarities of topoisomerase / DNA complex behaviour in isolated nuclei
1Solovyan V. T., 1Andreyev I. O.
  1. Institute of Molecular Biology and Genetics, NAS of Ukraine
    150, Akademika Zabolotnoho Str., Kyiv, Ukraine, 03680


The properties of topoisomerase II/DNA complex in nuclear preparations have been investigated. It has been shown that topoII/nuclear DNA complex functiones unitypically both in Mg2+- and in Ca2+-containing media. Unlike to the in vitro assay the treatment of topoII/nuclear DNA complex with EDTA resulted in increase of nuclear DNA cleavage rather than its rejoining. The nuclear topoII/DNA complex treated with SDS was found to acquire the capacity to subsequent SDS-independent nuclear DNA cleavage. The salient features of topoisomerase II/nuclear DNA complex are supposed to be due to the topoII enzyme involvement in higher level's chromatin compactization leading to the initial stabilization of topoII/nuclear DNA complex in vivo conditions. The availability in cells the different topoII/DNA complex variants of possible physiological value has been proposed.


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