Posted: April 28, 2009

(Nanowerk News) Sigma-Aldrich today announced the global release of MISSION® esiRNA, a pool of gene-specific siRNA that provides a novel and powerful approach to RNAi screening in mammalian cells. Unlike traditional synthetic RNAi, esiRNA incorporates a pool of hundreds of siRNAs against a single gene target. This new tool is designed to eliminate the trial and error approach of identifying a single siRNA for gene knockdown and ensures minimal off-target effects.
"MISSION esiRNA provides a powerful way to elucidate gene function in cell culture assays," said Dr. Supriya Shivakumar, global marketing manager for Functional Genomics at Sigma-Aldrich. "The pooled format, unlike anything else on the market, should enable researchers to knock down genes rapidly and cost-effectively. This is an exciting addition to our current MISSION lineup and provides an effective technology that will facilitate RNAi research for a broad base of scientists."
The technique offers a number of benefits over the traditional approach to single-siRNA gene knockdown. By targeting each gene target with a "super-pool" of siRNA, the trial and error approach of identifying a useful single siRNA is eliminated. In addition, the approach should ensure minimal risk of off-target effects and enables the use of one assay per gene. Development of the esiRNA approach was supported by the German BMBF program "GO-Bio" and developed by the Max Planck Institute for Cell Biology and Genetics (MPI-CBG) in Dresden, Germany.
Frank Buchholz, a research group leader at the MPI-CBG, has pioneered the use of the esiRNA technology in RNAi screens. "We are delighted to be partnering with Sigma-Aldrich to make esiRNA technology available to the research community," he said. "esiRNAs were invented in Mike Bishop's laboratory at UCSF almost 10 years ago. esiRNA has been a major research focus of my group ever since. Sigma-Aldrich's extensive experience and product range in RNAi are a perfect complement to our effort to produce efficient and specific esiRNAs."
Harvard Medical School, which has invested in a human genome-wide esiRNA library, is using esiRNA to help identify the human genes that enable HIV propagation. "The phenotypic results from the initial tests of MISSION esiRNA using our assay for finding HIV dependency factors demonstrated very effective knockdown over a wide range of genes," said Dr. Abraham Brass, a clinical research fellow at Harvard Medical School.
Harvard Medical School will soon incorporate the technology into a wider range of tests. Dr. Caroline Shamu, director of the ICCB-Longwood Screening Facility, which provides high-throughput screens of RNAi libraries for Harvard Medical School researchers, said, "We are looking forward to screening the MISSION esiRNA library at ICCB-Longwood."
esiRNA are endoribonuclease-prepared siRNAs synthesized by in vitro transcription of a 300-600-bp gene specific double-stranded RNA, followed by enzymatic digestion. This collection of siRNA-like molecules is then purified, resulting in a complex pool of siRNA molecules all targeting different sequences of a single gene.
Source: Sigma-Aldrich (press release)