RNA/DNA/PROTEIN FROM SAME SAMPLE??

[Andrew Schrader]

This method is very useful for isolating DNA from large samples and involves the use of 
high NaCl. The reference is Miller, SA etal.  (1988) Nucleic Acids Research 16 (3) 
1215.

The protocol is for whole blood, but I am sure that you could adapt it to your needs using 
the buffers and reagents normally used for lysis and washing cells.

Basically after the cells have been lysed (in around 3 ml of buffer), 2 ml of saturated 
NaCl is added and mixed gently for about 15 seconds. The cellulsr proteins may be pelleted 
by centrifugation at 2500 RPM (in an SS34 or JA-17) for 15 mintes at RT. The 
supernatant containing the DNA can then be decanted and spun again to remove residual 
protein.

The protein precipitate may be retained and 2 volumes of ethanol (RT) is added to the DNA 
solution. If enough DNA is present it precipitates in front of you and can be spooled to 
remove it. If only a small amount is precipitated, it may be spun at high speed in a carex 
tube and resuspended in TE or whatever.

I am not aware of a method for isolating RNA from tissue that is non toxic, howver, this 
protocol may be adapted in some way for this purpose. 

I hope that this helps you out in some way.


Andrew Schrader