Changes in the Topology of DNA Replication Intermediates: In vivo vs In vitro

Abstract

Most of the methods used to analyze DNA, including electrophoresis, electron microscopy or atomic force microscopy, involve de-proteinization, and it is well known that the removal of proteins affects DNA topology. After de-proteinization in vitro, the topology of replication intermediates changes significantly. A comprehensive analysis of the topological changes introduced during DNA isolation (de-proteinization) is important to get a better understanding of DNA topology in vivo. The topology of replication intermediates examined by electrophoresis, electron microscopy or atomic force microscopy in vitro does not necessarily represent the situation in vivo.