How can I avoid or remove genomic DNA contamination from the total RNA preparation?
Carry out all procedures in a "DNA-free" workspace (see FAQ 2654). Be sure to include any DNase treatment steps in the recommended RNA isolation procedure or treat RNA separately with RNase-free DNase followed by repurification using a spin-column based method. RNeasy Mini Kit can be easily combined with RNase-free DNase. Alternatively, kits like the RNeasy Plus Universal Tissue already include a DNA removal step. Be sure to double both the units of enzyme and the incubation time recommended by the RNase-free DNase manufacturer. To minimize DNA contamination in your RNA preparations, and avoid the need for supplemental DNase treatments, we recommend using the RT2 First Strand Kit, which includes a highly efficient genomic DNA elimination step before reverse transcription.
NOTE: Our Chemistries are not compatible with AMBION's Turbo DNA-Free Kits.