Syndecan-4 is a heparan sulfate proteoglycan (HSPG) that has recently become of interest in various fields due to its unique property of activating PKC-α, a protein known to trigger apoptosis in specific cell types. As a result, syndecan-4 is an attractive candidate, in combination with other proteins, for the regulation of apoptosis. Implementing siRNA in order to better study the function of this protein would be an invaluable tool for a wide variety of fields. As a result, Ambion has several pre-designed siRNA constructs available that specifically target Syndecan-4 for knock-down.
Unlike other companies, Ambion guarantees one of their three Syndecan-4 siRNA constructs to work in your cell type of interest. However, as the end user, you are required to optimize the transfection of your cells. If the constructs fail to deplete Syndecan-4 you must simply call the company, provide them with your order number as proof of purchase, and wait for them to design a new Syndecan-4 specific siRNA to be shipped to you. The main problem with this type of guarantee is that you, the end user, become the product tester for the company. As a result, Ambion may guarantee to continue to make siRNA constructs until you find one that works, but there is no guarantee on how many will have to be tested or how long it will take for you to find one that does work.
Although Ambion ships their pre-designed Syndecan-4 constructs very quickly and markets several products to simplify optimization, I have found that each construct failed to knock down expression in human fibroblasts. I contacted Ambion and requested they design new constructs. Overall, this process was relatively simple once I located the correct phone number to call regarding the problem, and the new constructs arrived within two weeks. However, the new constructs also failed to work and after going through this process several times, I have found myself now looking to other companies for additional Syndecan-4 constructs and design opportunities.
Offering pre-designed siRNA constructs will be just one of the many transformations in the constantly changing market of siRNA products. However, because the current constructs offered by Ambion are algorithm based and are mostly untested, there is no real advantage of having the constructs “pre-made”. In the future, these constructs will have been tested and optimized, making the pre-designed product a great money and time saving tool. Currently, however, Ambion offers no benefit over other companies offering similar services. Therefore, be aware that you will have to test and optimize the Syndecan-4 and any other pre-designed constructs as you would with those produced by other companies.
Amy Bellmeyer, M.S.
Research Technician
Northwestern University
Division of Pulmonary and Critical Care Medicine