Caesium chloride centrifugation

Total RNA can be prepared using commercially available kits according to the protocols of the manufacturer or by the guanidinium isothiocyanate method, followed by caesium chloride centrifugation (CsCl). Details are published in handbooks of molecular biology techniques. In our hands, both methods are equivalent, but if budgets are limited, the CsCl method may be more suitable for the preparation of large amounts of RNA. 

Figure 13.7 Caesium chloride density gradient centrifugation for (a) the separation of DNA from RNA and protein and (b) the separation of linear DNA and supercoiled DNA.

When total DNA is subjected to high speed density gradient centrifugation in caesium chloride, a large band of nuclear DNA and one or more small satellite bands are usually observed. Up to four satellite DNA bands have been detected in... 

For zonal density gradient centrifugation there are a number of media that can be used, however the most common of these is sucrose whereas the most common medium for isopycnic density gradient centrifugation is caesium chloride (CSCI2). 

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