What are the benefits of using a vector to deliver RNAi?
Vector technologies allow you to:
Achieve transient or stable target knockdown
Perform RNAi in any cell type, even hard-to-transfect, primary, and non-dividing cells
Regulate gene inhibition with inducible siRNA expression
Select for a pure population of cells stably expressing an siRNA sequence
Control gene expression in vivo with tissue-specific promoters
Find additional tips, troubleshooting help, and resources within our RNAi Support Center.
Why are my cells dying after transfection?
We would suggest running a transfection reagent control only to determine if your cells are sensitive to the transfection reagent. Additionally, you can try using different cell densities and siRNA concentrations to diminish any toxic effects from the transfection itself.
Find additional tips, troubleshooting help, and resources within our RNAi Support Center.
I transfected my siRNA and the mRNA levels are down, but the protein is not. Why is that?
In some cases, knockdown of a protein can be affected by other variables such as protein turnover rate, even though the RNA is knocked down. Additionally, a longer time course may be needed to see an effect on protein compared to mRNA.
Find additional tips, troubleshooting help, and resources within our RNAi Support Center.
I am not getting my target knockdown. What could be the cause of this?
Please see the following possibilities and suggestions:
- How many siRNA did you test? Is there any knockdown? If there is no knockdown (<10%) in any of the siRNA, then the assay is likely the problem. Try using a different qRT-PCR assay to assess knockdown.
- What was the positioning of the qRT-PCR assay target site relative to the cut site for the siRNA? If greater than 3,000 bases away, the problem could be alternative splice transcripts.
- What are the Cts for the experiment? They should be below 35 in a 40-cycle qRT-PCR experiment.
- Did you confirm the siRNA got into the cell? We recommend using a validated positive control siRNA to check the transfection efficiency.
Find additional tips, troubleshooting help, and resources within our RNAi Support Center.
I am not getting any knockdown with my siRNA. What do you suggest I try?
Please see the following possibilities and suggestions:
- Were the mRNA levels checked? The most reliable method is real-time PCR. In some cases, knockdown of a protein can be affected by other variables, such as protein turnover rate, even though the RNA is knocked down.
- How is the RNA being isolated? Has the quality of the isolated RNA been checked? Ensure that the RNA has not been degraded.
- Was a positive control used? This can help to determine whether the reagents are working and whether the siRNA was delivered correctly to the cell. Run your experiment in parallel with the positive control siRNA.
- Was a transfection control used? What is the percentage of transfected cells?
- Was a time course used? Generally, gene silencing can be assessed as early as 24 hours posttransfection. However, the duration and level of knockdown are dependent on cell type and concentration of siRNA.
- Was optimization of transfection conditions performed? You can try using different cell densities and siRNA concentrations.
- Which concentration of siRNA did you use? We recommend testing multiple concentrations between 5 nM and 100 nM.
Find additional tips, troubleshooting help, and resources within our RNAi Support Center.
