Preservation for RNA/DNA (using RNAlater)
This commercially available fixative is often used with success; other labs find it problematic. It is apparently not a good means for preserving microRNAs. Best practices are as follows:
A) Maintain a fixative:tissue ratio of 5:1 at least. More fixative is better.
B) Cut the tissue into very small pieces, e.g., 1-2 mm cubes.
C) Incubate overnight at room temperature.
D) Store at -20°C or -80°C.