title: Transcription is associated with Z-DNA formation in metabolically active permeabilized mammalian cell nuclei.
abstract: Mammalian cells have been encapsulated in agarose microbeads, and from these cells metabolically active permeabilized nuclei were prepared. Previously, we showed that biotin-labeled monoclonal antibodies against Z-DNA can be diffused into the nuclei and, over a specific concentration range, they will bind to Z-DNA within the nucleus in a concentration-independent manner. By using radiolabeled streptavidin, we showed that the amount of Z-DNA antibody bound is related to the torsional strain of the DNA in the nucleus. Relaxation of the DNA results in a decrease of Z-DNA formation, whereas increasing torsional strain through inhibiting topoisomerase I results in increased Z-DNA formation. Here we measure the influence of RNA transcription and DNA replication. Transcription is associated with a substantial increase in the binding of anti-Z-DNA antibodies, paralleling the increased level of RNA synthesized as the level of ribonucleoside triphosphate in the medium is increased. DNA replication yields smaller increases in the binding of Z-DNA antibodies. Stopping RNA transcription with inhibitors results in a large loss of Z-DNA antibody binding, whereas only a small decrease is associated with inhibition of DNA replication.
authors.affiliation: Institut für Molekularbiologie und Biochemie, Freie Universität, Berlin, Federal Republic of Germany.
authors.forename: B
authors.initials: B
authors.lastname: Wittig
authors.forename: T
authors.initials: T
authors.lastname: Dorbic
authors.forename: A
authors.initials: A
authors.lastname: Rich
mesh_terms: D000911:Antibodies, Monoclonal; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D004261:DNA Replication; D004273:DNA, Neoplasm / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D010539:Permeability; D014158:Transcription, Genetic
chemical_list: D000911:Antibodies, Monoclonal; D004273:DNA, Neoplasm