Western Blotting Services: Topo I,IIα,IIβ Protein Levels

TopoGEN can quantify topoisomerase I, IIa, IIb and III levels in your extracts using Western Blotting and utilize our immune-reagents for cell distribution or localization experiments.

We can also provide precise directions on making nuclear extracts and we will quantify topo levels by high resolution Western Blotting. The data will be publication quality with markers and precise quantitation.

Testing 'Band Depletions'

In this analysis we determine how well endogenous topo I or II is trapped onto genomic DNA. This is complementary to the In Vivo Link Kit. When cells are exposed to topo poisons, a fraction of the free enzyme becomes entrapped with high MW genomic DNA and cannot be extracted. This is reflected as a loss of band intensity of the nuclear extract, probed by Western blotting.

Testing Levels

of topo for biomarker or mechanistic studies with all human topo-enzymes.


Cyto-localization experiments of topoisomerases. 


with topoisomerases can be used to detect, quantify and recover either topoisomerases or Topo/DNA complexes.

All of the above can be carried out using our Screening Services: Independent Validation, Expediency, Value, Publication ready.

Our Screening Services: Independent Validation, Expediency, Value

At TopoGEN, we developed, trademarked and patented many of the technologies associated with drug effects on DNA. We are leading experts at drug testing and assessment of drug action from a mechanistic standpoint. When you engage our services, we will describe and lay out a logical/rational approach that is rich in content and strongly mechanistic. We offer independent consultants who can validate our findings. Our services offer expediency as well. We can significantly accelerate the pace of your research, produce publication quality data and you will own the intellectual property that comes with our studies. We routinely enter into confidentiality agreements on projects, so your results are protected. Our in-house testing program is flexible, fast and efficient.  You will receive publication quality data. The following are the “Top 10” reasons you should consider our screening services for your R&D needs:

All Postitive & Negative Controls

We demonstrate internally that all testing platforms are perfectly functional. As a result, there is no guessing. Your data will be clear and unambiguous. We stand behind our findings and certify the data.

All Markers Will be Included

To document and validate the results. Again, we certify tractable results that will be internally controlled.

Testing & Costing Flexibility

We tailor each contract to offer maximum flexibility and coordinate with you over the course of the project to ensure intellectual flow of ideas and results. We will advise you on the best course of action with all hits. You can select the level of detail for the project that best suits your needs.  In some projects, there will be a need to re-examine, re-test or alter the course. How do we correct for work-load adjustments in the mid-stream? Our solution: we include on all projects, a small indirect cost that will allow us to perform additional key experiments without asking for additional funds. This is an advantage for clients and ensures that our high standards of data quality will be maintained. For example, if additional testing regimens are required, we carry out the service automatically. Importantly, there is no guessing on the budget and you will not pay additional fees.


We are a team of topo experts. All projects include email and direct SKYPE support over the course of the project. Our scientific staff will discuss and suggest future prospects or experiments.


For complete flexibility and to ensure cost-effective contracts, we offer two levels of reporting. At a basic level, included in all contracts, we provide well-documented data (powerpoint, PDF or password protected cloud account). We draw conclusions, presented as bullets, on each slide and make a recommendation for further development and maturation of the project. For clients who wish to have a & ´manuscript´ style report, we offer fully referenced publication style reports. These reports are professionally prepared and are suitable for presentation to regulatory agencies. These publication style reports can be reviewed independently by third party opinion leaders in the field and the reviews appended to the final report.

Hands-on Experience

The company has been actively engaged in contract drug testing since the 1990s and we have the experience to get results that will enable ‘go/no go’ decision making on drug development.


In most cases, the project will be completed over a period of several business days. We will clearly stipulate how long the project will take and we deliver on time.

A Selection of Enzyme Targets

We can test prokaryotic and eukaryotic systems with highly purified enzymes that are well-controlled reagents. We can provide additional documentation of purity and QC on all preparations. The following enzymes or tractable antibodies are currently in our inventory:

        • Human DNA Topoisomerase I
        • Human DNA Topoisomerase IIα
        • E.  coli DNA Gyrase
        • S. aureus DNA Gyrase
        • E. coli Topoisomerase IV
        • S. aureus Topoisomerase IV
Advanced Testing in Living Cells

TopoGEN is a pioneer in testing agents that operate in the context of the cell. For eukaryotic systems, we can perform rigorous testing in tissue culture cells. We offer a variety of cell lines suitable for topo I, IIα and IIβ testing. For example, we can test your drug (either as CIC or IFP) in virtually any cell line of interest.

The "Dual Gel Analytical System"

TopoGEN is unique in offering this service as part of our routine testing regimen. In all projects, we design our experiments to garner new information about your compound. For example, all gels are run in duplicate. One is a non-EB gel system, used to demonstrate unambiguous catalytic activity and the other gel is an EB containing gel to parse clearly the cleavage products. Since the reactions come from the same tube, we can be sure that the results are reproducible and accurate. Importantly, the non-EB gel system also reports whether the drug is a DNA intercalator, which may suggest genotoxicity in cells.