Lower Cost & Higher Potency SiRNAs

Lower Cost & Higher Potency siRNAs

Significantly Reduce siRNA Preparation Costs with the Silencer™ siRNA Construction Kit

• Up to 20X the potency of chemically synthesized RNA oligonucleotides
• Make up to 15 siRNAs for the cost of chemically synthesizing just 1 siRNA
• Hundreds of transfections per reaction

Using siRNAs to Affect Gene Expression

RNA interference (RNAi) or gene silencing is a technique for down regulating the expression of a specific gene in living cells by introducing a homologous double-stranded RNA. It has recently been demonstrated that 21 base double-stranded RNA molecules (small interfering RNAs or siRNAs) are potent mediators of the RNAi effect in mammalian cells. Currently, not much is known about siRNA design. Typically, 3-5 double-stranded siRNA molecules are designed per gene in order to find an siRNA that has a strong effect. This means synthesizing and purifying 6-10 RNA oligonucleotides, at a minimum cost of $1500 per gene. Ambion has developed a system for siRNA synthesis and purification based on in vitro transcription, the Silencer siRNA Construction Kit (patent pending). It produces transfection-ready siRNA at a fraction of the cost of chemical synthesis. In addition, Ambion scientists find that siRNA produced with the Silencer siRNA Construction Kit is as much as 20X more potent than chemically synthesized siRNA of the same target sequence.

Don't Limit Your Research by Testing Only a Few siRNAs

The cost and time savings gained using the Silencer siRNA Construction Kit enable screening of more potential targets within your gene to find the most potent siRNA. Higher potency siRNA will mean better signal-to-noise ratios in your experiments because of fewer non-specific effects.

Construction of an siRNA begins with the acquisition of 2 inexpensive, desalted DNA oligonucleotides. As illustrated in Figure 1, these oligonucletides include an 8 base sequence complementary to the 5' end of the T7 promoter primer included in the Silencer siRNA Construction Kit. Each gene specific oligonucleotide is annealed to the supplied T7 promoter primer, and a fill-in reaction with Klenow fragment generates a double-stranded template ready for use in an in vitro transcription reaction. The 2 transcription reaction products are hybridized to each other, treated with DNase (to remove template) and RNase (to polish the ends of the double-stranded RNA), and column purified. The entire procedure requires less than 2 days, and is easily scalable — 15 siRNA molecules can be synthesized as easily as a single siRNA. Each transcription/purification produces enough siRNA for hundreds of transfections. The time required for double-stranded RNA synthesis and purification using the Silencer Kit is a fraction of the 1-2 week processing time typically required for RNA oligonucleotide synthesis via phosphoramidite chemistry and subsequent purification.