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Topo II and Topo I are not Equivalent Topological Adjustment Machines in vivo

Topo II and Topo I are not Equivalent Topological Adjustment Machines in vivo

In a recent report in Nucleic Acids Research, researchers provide evidence that topoisomerase I and II perform similar functions in vitro (relaxation of supercoiled DNA); however, the in vivo situation is very different. There are of course non-overlapping activities of type I and II enzymes, specifically, the latter are cell cycle regulated and provide decatenase activity which is essential for life. Still, topo enzymes provide other key functions that attend all aspects of template activation. From genetic complementation studies, topological…

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Study Aims to Broaden Understanding of The Propagation of Topological Domains in Eukaryotes

Study Aims to Broaden Understanding of The Propagation of Topological Domains in Eukaryotes

In this paper researchers have devised a very clever strategy to evaluate the genesis of topological domains. The basic idea is to design high affinity DNA binding sites for specific proteins as tandem copies within a single plasmid. Then, they tested whether it was possible to divide the plasmid into protein defined domains of constrained topological segments (or create topological barriers). This is a nice inroad to understand how topological domains can be propagated in linear chromosomes in eukaryotes. In…

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ICE Bioassay: Use and Application

ICE Bioassay: Use and Application

This short video describes how our in vivo Link kits for Topo I and Topo II allow the investigator to observe how drug action inside a tumor cell. Topo I in vivo Link Kit and Topo II in vivo Link Kit available from TopoGEN. Topo I in vivo Link Kit and Topo II in vivo Link Kit available from TopoGEN.

Astrazeneca Compounds Target Topoisomerases in vivo

Astrazeneca Compounds Target Topoisomerases in vivo

Kinase inhibitors are an important class of anticancer and anti-inflammatory compounds. Pharmaceutical companies rely on structure activity-genotoxicity evaluations to evaluate off target action of novel drugs (such Ames or other in vitro genotoxicity screens). Effective drugs should be highly targeted and not pleiotropic. Researchers at AstraZeneca have recently shown that promising compounds (that hit the desired target and appear to be non-genotoxic) may target topoisomerases in vivo or show other DNA reactive characteristics. Off target drug action is extremely important…

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New: Updated Kit Protocols…Now Available for Download!

New: Updated Kit Protocols…Now Available for Download!

We have updated the protocols of our most popular Topoisomerase Assay and Drug Screening Kits – better graphics, an FAQ section, and visual layouts that are easier on the eye.  Whats more is that these protocols are now available for download here!  Check back as we upload more protocols in the coming weeks.  The following new protocols are available on the Product Page for each kit under “Related Documents:” Human Topoisomerase II Assay Kit TG1001 Topoisomerase I Assay Kit TG1015…

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Topo I Enzyme Provided for Autoimmunity Study

Topo I Enzyme Provided for Autoimmunity Study

Immunization with DNA topoisomerase I and Freund’s complete adjuvant induces skin and lung fibrosis and autoimmunity via interleukin-6 signaling. Abstract OBJECTIVE: The presence of anti-DNA topoisomerase I (anti-topo I) antibody correlates positively with disease severity in patients with systemic sclerosis (SSc). However, the role of induction of anti-topo I antibody production and its potential contribution to the pathogenesis of SSc remain unclear. The aim of this study was to examine the role of anti-topo I antibody in the pathogenesis of…

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Study: Geminin Silencing Inhibits Topo II Function

Study: Geminin Silencing Inhibits Topo II Function

The Topo II Assay Kit is arguably our most simple and tractable diagnostic, making it one of our most popular products for novel chemo-therapuetics research.  Referenced here is a study that utilized the assay to monitor topoisomerase II enzyme in relation to the presence of geminin in human breast cancer cells.  The findings indicate that targeting geminin has therapeutic potential in the study of cancer cells and drug resistance.  This work opens up the prospect of using geminin as a…

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Emodin: Topo II Inhibitor and Poison

Emodin: Topo II Inhibitor and Poison

In this work, the authors demonstrate very nicely the mode of action of emodin, an active anthraquinone natural product from plants and fungi (and used as a laxative).  This widely used drug is genotoxic and is a carcinogen.  Its mode of action is unclear and this work defines it as a topo II inhibitor and poison.  They propose a mechanism involving both cleavage stabilization and inhibition of ATP hydrolysis.  The key experiments involved using the ICE bioassay to examine in…

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New Topoisomerase II Inhibitor Study

New Topoisomerase II Inhibitor Study

This Merck study was published in Cell and showcases the use of our E. coli DNA Gyrase and Topo IV assay protocols in identifying a new class of Topo II inhibitor.  The following type II topoisomerases were provided for the study by TopoGEN: E. coli DNA Gyrase, Topoisomerase IV.  The following plasmids were also provided by TopoGEN: pBR322, kDNA. Article Source: Cell Website

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