Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Plant Mol Biol
1992 May 01;192:265-76. doi: 10.1007/bf00027348.
Show Gene links
Show Anatomy links
In vitro analysis of a type I DNA topoisomerase activity from cultured tobacco cells.
Cole AD
,
Heath-Pagliuso S
,
Baich A
,
Kmiec EB
.
???displayArticle.abstract???
The role of DNA topoisomerases in plant cell metabolism is currently under investigation in our laboratory. Using a purified type I topoisomerase from cultured tobacco, we have carried out a biochemical characterization of enzymatic behavior. The enzyme relaxes negatively supercoiled DNA in the presence of MgCl2, and to a lesser extent in the presence of KCl. Phosphorylation of the topoisomerase does not influence its activity and it is not stimulated by the presence of histones H1 or H5. The enzyme may act in either a processive or distributive manner depending on reaction conditions. The anti-tumor drug, camptothecin, induces significant breakage by the enzyme on purified DNA molecules unless destabilized by the addition of KCl. The tobacco topoisomerase I can catalyze the formation of stable nucleosomes on circular DNA templates, suggesting a role for the enzyme in chromatin assembly.
Been,
DNA strand breakage by wheat germ type 1 topoisomerase.
1984, Pubmed
Been,
DNA strand breakage by wheat germ type 1 topoisomerase.
1984,
Pubmed
Brougham,
Topoisomerase from Ustilago maydis forms a covalent complex with single-stranded DNA through a phosphodiester bond to tyrosine.
1986,
Pubmed
Champoux,
Proteins that affect DNA conformation.
1978,
Pubmed
Champoux,
An activity from mammalian cells that untwists superhelical DNA--a possible swivel for DNA replication (polyoma-ethidium bromide-mouse-embryo cells-dye binding assay).
1972,
Pubmed
Champoux,
The effects of camptothecin on the reaction and the specificity of the wheat germ type I topoisomerase.
1989,
Pubmed
Covey,
Protein-linked DNA strand breaks induced in mammalian cells by camptothecin, an inhibitor of topoisomerase I.
1989,
Pubmed
Echeverria,
A DNA topoisomerase type I from wheat embryo mitochondria.
1986,
Pubmed
Gilmour,
Localization of specific topoisomerase I interactions within the transcribed region of active heat shock genes by using the inhibitor camptothecin.
1987,
Pubmed
Glikin,
Chromatin assembly in Xenopus oocytes: in vitro studies.
1984,
Pubmed
,
Xenbase
Heath-Pagliuso,
Purification and characterization of a type-I topoisomerase from cultured tobacco cells.
1990,
Pubmed
Hsiang,
Camptothecin induces protein-linked DNA breaks via mammalian DNA topoisomerase I.
1985,
Pubmed
Kaiserman,
Regulation of Xenopus laevis DNA topoisomerase I activity by phosphorylation in vitro.
1988,
Pubmed
,
Xenbase
Kmiec,
Studies on the ATP requirements of in vitro chromatin assembly.
1989,
Pubmed
,
Xenbase
Laemmli,
Cleavage of structural proteins during the assembly of the head of bacteriophage T4.
1970,
Pubmed
Liu,
Eukaryotic DNA topoisomerases: two forms of type I DNA topoisomerases from HeLa cell nuclei.
1981,
Pubmed
Maxwell,
Mechanistic aspects of DNA topoisomerases.
1986,
Pubmed
Morse,
Nucleosomes inhibit both transcriptional initiation and elongation by RNA polymerase III in vitro.
1989,
Pubmed
,
Xenbase
Nielsen,
Pea chloroplast topoisomerase I: purification, characterization, and role in replication.
1988,
Pubmed
Rowe,
Purification and properties of a topoisomerase from Ustilago maydis.
1981,
Pubmed
Sekiguchi,
Studies on DNA topoisomerase activity during in vitro chromatin assembly.
1988,
Pubmed
,
Xenbase
Sekiguchi,
Changes in DNA topology can modulate in vitro transcription of certain RNA polymerase III genes.
1989,
Pubmed
,
Xenbase
Shaffer,
Vaccinia virus encapsidates a novel topoisomerase with the properties of a eucaryotic type I enzyme.
1987,
Pubmed
Shuman,
Identification of a vaccinia virus gene encoding a type I DNA topoisomerase.
1987,
Pubmed
Singleton,
The facile generation of covalently closed, circular DNAs with defined negative superhelical densities.
1982,
Pubmed
Stevnsner,
Interactions between eukaryotic DNA topoisomerase I and a specific binding sequence.
1989,
Pubmed
Wang,
DNA topoisomerases.
1985,
Pubmed
