1. Why should I use CytoSections in my research when I have tissue control?
Most often researchers find it very challenging to find a good positive control tissue. For example, getting a human tissue to study PDL1. Without a proper control, data interpretation becomes very challenging often leading to inaccurate analysis. OriGene offers more 20,000 CytoSections where the expression of target protein is verified. For example, we offer 4 CytoSections where expression of PDL1 protein is verified. The expression is not only verified but is also available in unlimited quantify as these are cultured in the laboratory.
2. For how many targets are CytoSections available?
OriGene offers CytoSections for more than 20,000 human and mouse targets.
3. How are CytoSections validated?
CytoSections are generated by expression of TrueORF cDNA clones in human HEK293 cells. The accuracy of target protein in CytoSections is verified by sequencing of the target TrueORF cDNA clone in the expression vector and the expression of the target protein is validated by Western blot.
4. Should I use CytoSections or primary tissue for my experiment?
Primary tissue is always optimal, but it is often difficult to find a primary tissue that stain consistently for the target for the entire block. CytoSections provide uniform expression pattern for the block no matter how far you section in the block, hence CytoSections is an ideal alternative control tissue.
5. Can CytoSections be used for any downstream application (e.g. commercial, genomic, in situ etc.)?
Yes. Currently we have tested it only for immunohistochemistry applications.
6. How do I determine if my primary antibody is picking up the correct positive cell in a section?
For each gene target, OriGene offers not only a CytoSection, where the expression of target protein is confirmed but also a negative control of mock transfection thus no target protein is expressed. When you run the appropriate CytoSections along with your sample, a positive signal in both the CytoSection and the tissue and no staining in the negative control, tells you that you are detecting the correct target positive cell. You can also stain the CytoSections for the Myc-DDK tag which will confirm the presence of the target protein clone. For DDK detection recommend you use OriGene’s mouse anti-DDK clone 11C3 TA180144, which works very well in ICC.
7. Can you develop CytoSections expressing a mutant protein?
Yes. We can develop a mutant clone for any target, express it in human cells, verify its expression by western blot using antibodies to Myc-DDK tag. There is a possibility that the protein is toxic to cells and is not expressed. In such cases we can try multiple cell lines. The project will be offered as a custom project, so please talk to our tech support team.
8. What is the turn-around-time (TAT) for CytoSections?
For most CytoSections, the TAT is 4-6 weeks from the time we get a confirmed order. Please note that all CytoSections are made to order, hence there can be delays. These will be conveyed when you place the order.
9. What are the terms of OriGene’s CytoSection guarantee about target expression?
The expression of each target clone is verified by western blot with antibodies to the Myc-DDK tag. With the western blot, we not only verify the expression of the clone but also ensure that the expressed protein matches with the predicted molecular weight. We do not test for the expression of target gene but do offer it as a special service.
10. How should I store CytoSections?
CytoSections are like a FFPE tissue section, hence should be treated the same and should be stored at room temperature.
11. How should I cite your product?
Here is our guideline: Full Product Name, OriGene Technologies Inc., Rockville, MD, USA, Catalog #, Lot #.
In addition, we would love to hear from you when the paper is published. Email us a copy of the accepted manuscript and receive a special gift.
12. Do you have negative controls?
Yes. We offer negative controls which includes HEK293 cells just transfected with vector alone. These will show a positive staining if stained for the Myc-DDK tag. These are excellent resources for IHC process controls.
13. What is the difference between ICC, IHC and CytoSections™?
Immunocytochemistry (ICC) and Immunohistochemistry (IHC) are frequently used interchangeably even though there is a significant different between them. The key difference is in the sample type that is analyzed.
IHC is a staining process that is performed on tissue samples that are formalin fixed and embedded in paraffin. These FFPE blocks are cut into thin sections and placed on slide for staining. ICC is a staining process that performed on cultured monolayer cells or cultured cells in suspension that are deposited on coverslips or slides. CytoSections are cultured human cell pellet over-expressing a specific target protein that are fixed in formalin and embedded in paraffin to generate FFPE blocks. These FFPE blocks are cut into thin 4–5-micron sections and placed on SuperFrost slides to be processed like a FFPE tissue section.
A striking advantage of a CytoSection is that it behaves just like an FFPE tissue, hence it is a ideal alternative to tissue control especially in situations where a validated positive control expressing the target is scarce or is not available.