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Embryogenesis and Topo I: Screening for Cheaters

Embryogenesis and Topo I: Screening for Cheaters

The authors have used a clever genetic screen to identify “Cheater mutations” in genes that confer the ability of cells to behave in a non-cooperative fashion in a tissue context. These cheater cells could for example, outgrow surrounding cells as aberrant clones, and thereby derail a tightly regulated process of differentiation that is pivotal in development. A very nice bioinformatic rendering of the data revealed that an axis of regulatory genes that are under the influence of topoisomerase I and…

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Mutations and Drug Resistance: Topo I and Irinotecan

Mutations and Drug Resistance: Topo I and Irinotecan

Low efficacy of a particular class of anti-cancer agents is discussed in this article. The authors hypothesize that Topoisomerase I mutations cause a resistance to Irinotecan, a commonly used drug for the treatment of colon cancer. Article Source: Molecular Cancer New Topoisomerase I mutations are associated with resistance to camptothecin Abstract Background: Topoisomerase I (TOP1) is a nuclear enzyme that catalyzes the relaxation of supercoiled DNA during DNA replication and transcription. TOP1 is the molecular target of camptothecin and related…

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Findings on the Dissasemblage of Particular Nuclear Subdomain in Tumor Cells

Findings on the Dissasemblage of Particular Nuclear Subdomain in Tumor Cells

The authors discuss the particulars of the perinucluear compartment in DNA and its effects on the DNA integrity of a tumor rich environment. Human Topo I Antibody provided by TopoGEN. Article Source: The Journal of Biological Chemistry The Perinucleolar Compartment Is Directly Associated with DNA Abstract The perinucleolar compartment (PNC) is a nuclear subdomain that is unique to tumor cells, and the percentage of cells in a population containing PNCs (PNC prevalence) indicates the level of malignancy of that population….

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Quantifying Topo Action in E. Coli

Quantifying Topo Action in E. Coli

A new method to quantify endogenous Topoisomerase action in E. coli cells is nicely described in this paper. The technique is based on the In Vivo Link Kit, also known as the ICE bioassay. Article Source: American Society for Microbiology Isolation and Quantitation of Topoisomerase Complexes Accumulated on Escherichia coli Chromosomal DNA Abstract DNA topoisomerases are important targets in anticancer and antibacterial therapy because drugs can initiate cell death by stabilizing the transient covalent topoisomerase-DNA complex. In this study, we…

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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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