Can a QIAquick Gel Extraction Kit be used to obtain RNA from a formaldehyde gel?

Yes. The QIAquick Gel Extraction Kit for extraction of DNA from gels can also be used for RNA gel extraction. Please see a user-developed procedure below, which was kindly provided by J. Knobloch, Heinrich Heine University, Düsseldorf, Germany. Note that this protocol has not been thoroughly tested and optimized by QIAGEN. QIAquick Gel Extraction Kits are not guaranteed to be RNase-free.

1. Excise the RNA fragment from the formaldehyde agarose gel with a clean, sharp scalpel.
2. Weigh the gel slice, and record the weight. Soak the gel slice in TE buffer for 25 min at room temperature with gentle shaking.
3. Remove the gel slice from the TE buffer, and place it in a colorless tube. Add 6 volumes of Buffer QG to 1 volume of gel, based on the gel weight (100 mg ~ 100 µl).
4. Incubate at 58°C for 25 min. To help dissolve the gel, mix by vortexing the tube every 2–3 min during the incubation.
5. Continue the QIAquick Gel Extraction Kit Protocol (using a microcentrifuge) in the QIAquick Spin Handbook, beginning with step 4.

Please click here  for Figure 1. 

Figure 1:

A. Total RNA was isolated from the parasitic blood fluke Schistosoma mansoni using the RNeasy Mini Kit and run on a formaldehyde agarose (1.2%) gel. (Note: The 28S rRNA in S. mansoni contains a break site so that the rRNA splits into two parts, which run on a gel at the same size as the 18S rRNA.) The rRNA bands were excised and treated as described above (left lane) or using 10 volumes of Buffer QG in step 3 (right lane).

B. The extracted RNA was then analyzed on a new formaldehyde agarose gel. (Data kindly provided by J. Knobloch, Department of Genetic Parasitology, Heinrich Heine University, Düsseldorf, Germany).