TRIzol (25ml) For RNA Extraction
tissue in CBSATRIzol to the point of an
RNA pellet in 75% ethanol, takes less than 1 hour. The RNA can then be stored for long periods of time, at -20°C. The same protocol can be used for RNA extraction from cell cultures. For further use of the RNA for expression analysis, it is highly recommended to treat the sample with DNase, an enzyme that digests DNA. This procedure is very effective for isolating RNA molecules of all types from 0.1 to 15kb in length. However, there are commercial kits that enable simple RNA extractions, usually using a column that binds the RNA, and also include the DNase treatment in them. Moreover, inherent to methods that use phenol-chloroform for RNA isolation and cleanups is a certain loss of total RNA. This varies in percentage depending on the sample size (the larger the amount of total RNA, the smaller the relative loss). I therefore recommend using this protocol for RNA isolations from large number of cells. However, once laser microbeam dissected RNA extraction from cells will be considered, I strongly recommend using a different method, preferably a suitable kit for such extractions. This modification could be considered also in the case of RNA extraction from sensory epithelia.