Preparation of RNA Samples from Mouse Tissues

Safety Information

• SOP - Phenol
• SOP - Chloroform

Materials

• PureLink RNA Mini Kit (Invitrogen cat#12183-018A)
• Mouse Tissue (50-100 mg, about a 3mm cube)
• TRIZol (Invitrogen cat# 12183-555)
• Chloroform (in solvent cabinet)
• Label tubes, for each sample need: 2.0 mL tube (to cut sample into), 1.5 mL tubes (X2), 1 spin column*, 1 recovery tube*, 1 collection tube* (*= in the PureLink kit)
• 70% Ethanol make with RNAase free water and 100% Ethanol.

Protocol

1. Cut ~50-100 mg of tissue. If tissue is in RNAlater, cut at room temperature. If tissue is frozen, cut on dry ice. Weigh into a fresh 2mL eppendorf tube and keep on ice.
2. Add 1 mL TRIzol reagent to each 2 mL tube.
3. Add 1 ball bearing to each tube.
4. Using tissue grinder, homogenize tissue for 3 minutes at 25 Hz (make sure there are no remaining clumps, maybe take longer for muscle). If chunks remain after 3 minutes, homogenize until chunks are gone in 2 minute increments.
5. Incubate 5 minutes at room temperature.
6. Transfer sample to a new 1.5 vial. The ball bearings are reusable after cleaning so do not discard them.
7. Add 200 uL Chloroform and shake vigourously by hand for 15 seconds. Do NOT vortex.
8. Incubate at room temperature for 2-3 minutes.
9. Centrifuge in a cold eppendorf centrifuge (4C) on maximum for 15 minutes. Sample will separate into a lower, red chloroform phase, an interphase and a colorless upper phase which contains the RNA. (WAT tissue may separate into 3 phases, RNA is the top, colorless phase.
10. Add 400 uL of 70% ethanol to a fresh tube.
11. Carefully transfer 400 uL of the upper phase to the ethanol tube and mix by vortexing. The remaining chloroform in the previous vial should be disposed of in the phenol waste container under the hood.
12. Remove 700 uL of ethanol/upper phase mixture (invert briefly to mix before taking sample) and add to a spin column in a collection tube.
13. Spin 15 seconds on max. Discard flow through. Add remaining sample, respin and discard flow through.
14. Add 700 uL Wash Buffer I to spin column.
15. Spin 15 seconds on max. Discard flow through and collection tube, add a new collection tube.
16. Add 500 uL Wash Buffer II (make sure ethanol was added to the wash buffer) to the spin cartridge.
17. Spin 15 seconds on max. Discard the flow through and keep the same collection tube.
18. Repeat wash by adding 500 uL Wash Buffer II to the spin cartridge.
19. Spin 15 seconds on max. Discard the flow through and keep the same collection tube.
20. Spin 1 minute on max to dry the cartridge. Discard the collection tube and place spin column into a clean recovery tube. Add 100 uL RNAase free water to the center of each tube. This can be adjusted to between 30 and 300 uL elution buffer if necessary.
21. Incubate at room temperature for 1 minute.
22. Spin 2 minutes at 12500 rpm to get purified RNA.
23. Quantify the RNA using the nanodrop.