Requirement of DNA topoisomerases for in vitro chromatin assembly by 3T6 mouse cell extracts

Nuclear extracts of 3T6 mouse cells were able to assemble in vitro minichromosomes which displayed a 150‐bp periodicity. Activities of both DNA topoisomerases I and II were detected in these extracts. When a supercoiled pUC DNA was added, it was first relaxed in less than 3 min, then slowly supercoi...

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Detalles Bibliográficos
Autores principales: CÁCERES, J.F., BLANGY, D., GLIKIN, G.C.
Formato: JOUR
Materias:
DNA
DNA topoisomerase
DNA topoisomerase (ATP hydrolysing)
animal
article
cell culture
chromatin
DNA supercoiling
isolation and purification
kinetics
metabolism
mouse
Animal
Cells, Cultured
Chromatin
DNA Topoisomerases, Type I
DNA Topoisomerases, Type II
DNA, Superhelical
Kinetics
Mice
Support, Non-U.S. Gov't
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00142956_v181_n2_p531_CACERES
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
Descripción
Sumario:Nuclear extracts of 3T6 mouse cells were able to assemble in vitro minichromosomes which displayed a 150‐bp periodicity. Activities of both DNA topoisomerases I and II were detected in these extracts. When a supercoiled pUC DNA was added, it was first relaxed in less than 3 min, then slowly supercoiled again in 1–4 h. Both reactions occurred either in the absence or the presence of added Mg2+ and/or ATP, they were not blocked by DNA topoisomerase II inhibitors and they were inhibited by an antiserum against DNA topoisomerase I and by camptothecin. These findings led us to propose that, under our in vitro assay conditions, chromatin assembly is mainly carried out by a DNA topoisomerase I. Copyright © 1989, Wiley Blackwell. All rights reserved

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