Regulation of the function of eukaryotic DNA topoisomerase I: topological conditions for inactivity.
- 1 May 1989
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences of the United States of America
- Vol. 86 (9), 3080-3084
- https://doi.org/10.1073/pnas.86.9.3080
Abstract
The effects of supercoiling on the cleavage reaction by eukaryotic DNA topoisomerases I (wheat germ, chicken erythrocyte, and calf thymus) have been analyzed on DNA fragments (0.96 and 2.3 kilobases) encompassing an immunoglobulin .kappa. light-chain promoter. In one topological condition of the substrate, the absolutely relaxed state, cleavage was found to be impeded. This finding defines the topology-dependent step of the eukaryotic DNA topoisomerase I reaction and shows that for the cleavage reaction topology is more critical than sequence effects. These findings suggest a simple model for the regulation of the DNA topoisomerase I reaction based on topological factors, which may explain the regulatory function of the enzyme in in vivo eukaryotic transcription.This publication has 25 references indexed in Scilit:
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