[Role of supranucleosomal structures of chromatin in the uneven distribution of DNA-bound 7,12-dimethylbenz(a)anthracene metabolites formed in vivo or in the perfused rat liver].

It was demonstrated that the DNA closely associated with the nuclear matrix preferentially binds 7,12-dimethylbenz(a)anthracene (DMBA) metabolites. In experiments with perfused rat liver, it was found that the kinetic curves for adduct formation in all DNA fractions of DNP have maxima, the largest differences in the rate of metabolite binding in the DNA fractions being observed at the initial moment of perfusion. There is evidence that the preferential binding of DMBA metabolites to matrix DNA is due to the increased accessibility of the DNA to the metabolites rather than to its proximity to the nuclear membrane. This accessibility, in its turn, is due to the peculiarities of the supranucleosomal structure of transcriptionally active DNP fragments associated with the nuclear matrix.