RNA Isolation Basic Considerations

Unlike DNA, RNA is very susceptible to rapid degradation due to ribonu-cleases (RNases), which are highly stable RNA degrading enzymes. In addition, RNA is more labile than DNA, especially at higher temperatures ( 65°C) and at alkaline pH ( 9). The sensitivity of RNA toward alkaline hydrolysis can be used for selective hydrolysis of RNA in a mixture of RNA and DNA [5], Isolation of intact RNA is crucial to the success of many applications, such as the measurement of qualitative and quantitative changes in gene expression, preparation of cDNA or cDNA libraries, and in the synthesis of a probe for various molecular hybridization experiments. 

The methods of RNA isolation depends on the tissue and type of RNA to be extracted. Procedures to isolate total cellular RNA include chemical extractions and centrifugation. mRNA is isolated from total RNA using affinity chromatography or magnetic beads, while high-pressure liquid chromatography methods are used for small RNA molecules. Phenol extraction was one of the first techniques to isolate RNA successfully from many sources 

Redissolve RNA Digest contaminating DNA Reprecipitate RNA with alcohol Centrifuge 

Salt and Stock Solution Concentration Salt Concentration in RNA Solution before Addition of Alcohol 

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