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Updated: Aug 12, 2026

Study of the DNA Damage Checkpoint using Xenopus Egg Extracts
Published on: November 5, 2012
DNA supercoiling by Xenopus laevis oocyte extracts: requirement for a nuclear factor
Abstract:
A purified system is described for the introduction of negative supercoils into simian virus 40 DNA. The system consists of histones H2A, H2B, H3, and H4, DNA-relaxing enzyme, and a purified factor from Xenopus laevis stage 6 oocyte nuclei. The nuclei are prepared en masse by the technique of F. Scalenghe, M. Buscaglia, C. Steinheil, and M. Crippa [(1978) Chromosoma 60, 299-308]. The supercoiled simian virus 40 DNA prepared by this method is indistinguishable from simian virus 40 supercoiled DNA prepared from infected monkey cells.
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