Interaction of DNA with cytosolic 3-methylcholanthrene binding proteins from either rat or mouse liver

Abstract

The ability of cytosolic 3-methylcholanthrene binding proteins from rat liver to interact with DNA was studied using DNA-cellulose chromatography. Two DNA binding fractions, eluting in 0.15 M KCl (peak 1) and 0.33 M KCI (peak 2), were observed on salt elution from a denatured DNA-cellulose column which had been incubated with rat liver cytosol containing radiolabelled 3-methylcholanthrene. No detectable DNA binding fractions were found when columns containing cellulose alone or native DNA-cellulose were used. Temperature activation of the cytosolic proteins containing 3-methylcholanthrene did not result in a significant difference in DNA binding characteristics when compared with a non-treated sample. The pretreatment of rats with Aroclor 1254 induced peak 1 3.7 fold over control values. An analysis of the proteins present in peaks 1 and 2 from control and induced rats was carried out using sodium dodecyl sulfate polyacrylamide gel elctrophoresis. Comparative DNA-cellulose chromatography of cytosolic liver proteins from a cytochrome P-448 inducible mouse strain (C57BL/6J) and non-inducible mouse strain (DBA/2J) showed much higher levels of DNA binding by protein bound 3-methylcholanthrene from C57BL/6J hepatic cytosol.