Rapid isolation of carcinogen-bound DNA and RNA by hydroxyapatite chromatography.

Carcinogen-bound DNA and RNA are conveniently isolated by solvent extraction and hydroxyapatite (HAP) chromatography. Tissue is suspended in 8 M urea-0.24 M sodium phosphate-1% sodium dodecyl sulfate-10 mM EDTA, pH 6.8 (MUP-SDS-EDTA) and extracted with chloroform-isoamyl alcohol-phenol (24:1:25; CIP) to remove protein. RNA and DNA are separated by passing the aqueous solution through an HAP column; RNA is eluted with MUP, DNA with 0.48 M sodium phosphate, pH 6.8. Examples presented are: (1) calf thymus DNA that has been reacted with N-acetoxy-2-acetylaminofluorene (N-OAc-AAF), (2) isolated intact rat hepatocytes incubated with N-hydroxy-AAF and (3) livers from Sprague-Dawley rats treated with N-hydroxy-AAF.