AMBION RELEASES siRNA LIBRARIES, INCLUDING A HIGHLY VALIDATED KINASE siRNA LIBRARY

Austin, TX, December 12, 2003 – Ambion, The RNA Company, announced today the launch and availability of two siRNA libraries: the first targets 597 human kinases and the second targets 441 human G protein-coupled receptors (GPCRs). The kinase siRNA library includes one or more functionally validated siRNAs targeting 231 kinases. These "validated" siRNAs have been functionally proven to efficiently decrease target mRNA levels. The empirical testing and validation of chemically synthesized siRNAs, which greatly increases downstream data reliability, is the hallmark of the Ambion siRNA product line. The proteins from the kinase and GPCR gene families represent well over one third of all targets for existing pharmaceuticals on the market. Additionally, these gene families are involved in almost every biochemical pathway within mammalian cells, from metabolic and cell signaling pathways to cell proliferation and apoptotic pathways.

The siRNAs included in the Silencer™ siRNA Libraries are designed using the industry-leading siRNA design algorithm developed by Ambion's partner, Cenix BioScience. Of the hundreds of siRNAs tested, approximately 80% were able to reduce target mRNA levels by greater than 70%, demonstrating the high success rate of the algorithm. To date, no other algorithm has been tested on as many siRNAs targeting as many different endogenous genes. The Silencer Kinase siRNA Library includes hundreds of validated siRNAs that have been proven to reduce target mRNA levels by 70% or more, which increases the quality and reliability of the data collected from experiments performed with the library.

"The large number of validated siRNAs in the Silencer Kinase siRNA Library, as well as the power of the siRNA design algorithm used, makes this library the best RNAi tool on the market," commented Matt Winkler, Ph.D., CEO and CSO of Ambion. “These new kinase and GPCR siRNA libraries will make an immediate impact on drug discovery programs. Plus, these libraries allow any researcher to better study the function of a large range of genes, pathways, and interesting phenotypes.”

Kinases are key participants in various regulatory and metabolic pathways. Using the Silencer Kinase siRNA Library to individually or combinatorially knock down kinases will allow a better understanding of each kinase's function and its participation in one or more biological pathways. GPCRs are a cell's signaling gateway to the outside world and are targeted by about one third of the drugs approved by the FDA. Silencing GPCR gene expression using siRNA provides an effective method to study this class of genes.

RNA-mediated interference, or RNAi, is a powerful approach for achieving targeted gene silencing of genes using complementary, double stranded RNA to trigger the effect. RNAi is a naturally occurring mechanism found widely in nature, from plants to humans. When applied in vertebrate systems, including cultured human cells, the RNAi pathway is most readily triggered through the use of short interfering dsRNA molecules, or siRNAs. As a result, siRNA has rapidly become the tool of choice for a wide range of biomedical applications. In particular, it has emerged as the best new functional genomics screening method to identify and validate new therapeutic drug targets.

Ambion, Inc., is a leader in the development and supply of innovative RNA-based life science research and molecular diagnostic products. Ambion has taken a leadership role in developing products for handling, preserving, isolating, detecting and measuring RNA in areas such as molecular biology, cell biology, microbiology, drug discovery and genomics. Thanks to a concentrated effort over the last two years, Ambion also provides the widest range of products and services for RNAi applications. For more information, please visit the company's web site, www.ambion.com.