[Molecular mechanisms of damage to fractionated liver chromatin by tetrachloromethane]

Impairing effects of tetrachloromethane on genetic apparatus were shown to consist in its high affinity and binding to transcriptionally active fraction of chromatin and subsequent destruction of DNA. As a result of the impairment the density of the chromatin fraction was increased which expressed as elevated stability to hydrolysis by endogenous nucleases. At the same time, content of single-stranded structures enriched with proteins was increased in the DNA of the transcriptionally active fraction of chromatin. Two dissimilar properties were detected in the fraction of impaired chromatin from the poisoned animals: increase of density in the chromatin fraction accompanied by insensitivity to S1-nuclease, which was detected after denaturation of chromatin and slight relaxation of apparently supernucleosome structures where content of sites, sensitive to short-term treatment with DNAase I, was increased. The hypothesis of the tetrachloromethane toxic effect on genetic apparatus is considered, according to which lipid moiety of chromatin and activation of lipid peroxidation are of definite importance in effects of the xenobiotic on chromatin.