This Ambion® vector is for the expression of siRNA. It has an antibiotic resistance gene （hygromycin） to enable selection of transfected cells and features the human RNA polymerase III promoter （U6）. Sufficient reagents are provided for 20 reactions.

• Select transfected cells to enrich the population of cells expressing your siRNA 
• Eliminate the need to synthesize RNA oligonucleotides for RNAi experiments
• Supplied linearized and ready for ligation

Compensate for Low Transfection Efficiencies and Perform Long-Term Studies
The use of mammalian siRNA expression vectors with antibiotic selectable markers conveys many benefits. Selectable markers can help compensate for poor plasmid transfection efficiencies seen with some cell lines. In these cases, only a fraction of the transfected cells express the siRNA, and reduction in target gene expression with even a potent siRNA can be difficult to detect. Use of a selectable marker and transient antibiotic selection permits.