Metal constituents of chromatin. Interaction of mercury in vivo

A zinc‐finger like metal binding site in the nucleosome

“…Similar results were obtained using cultured rat fibroblasts [48]. The Hg(II) contents in control mice was one atom per 10 000 bp, while in exposed animals it reached one atom per 1000 bp, corresponding to one Hg(II) ion per five nucleosomes [46]. The selectivity of binding was demonstrated to depend on the protein component of chromatin.…”

“…Both were in fact addressed, while indirectly, many years ago. Considering the first issue, intranuclear Hg(II) was detected virtually exclusively in euchromatin in both control and mercury chloride-challenged mice [46,47]. Similar results were obtained using cultured rat fibroblasts [48].…”

Histaminergic Pathway in Rat Brain Evidenced by Lesions of the Medial Forebrain Bundle

“…However, nuclear constituents such as nonhistone residual protein, RNA, phosphoprotein, and phospholipid were found to be present in a significant excess within euchromatin as compared to (repressed) heterochromatin; in particular, an excess of nonhistone residual protein is present within (active) euchromatin (7). On the basis of Chanda and Cherian's findings, in which mercury is bound largely to insoluble nonhistone protein, and of our present experiments, in which mercury is bound to eeuchromatin, in addition to our experiments reported previously (3), it seems likely that mercury is bound in a metalprotein (most likely nonhistone) complex within the euchromatin component of chromatin. The possibility of proteinmetal-DNA or metal-DNA complexes, however, cannot be ruled out.…”

“…Subcellular fractionation of brain homogenates reveals that a significant portion of the amine as well as of its specific synthesizing enzyme (L-histidine decarboxylase) (2) is apparently localized in nerve terminals (3)(4)(5). Neuronal receptors to histamine are apparently present in the brain, since the exogenous amine has been reported to induce electrical responses (6), behavioral effects (7,8), and activation of cyclic adenosine monophosphate formation (9); in all cases, these effects were antagonized by classical antihistamines.…”

“…Interferon induction can be considered a stringent biological test for the double-strandedness of polyribonucleotides, since double-stranded RNA's are markedly more effective as interferon inducers than their singleand triplestranded counterparts (1)(2)(3)(4). Primary rabbit kidney cell cultures are among the most sensitive cell types for assaying the interferon-inducing capacity and antiviral activity of double-stranded RNA's (5, 6), and their responsiveness is even enhanced when the cells are treated with metabolic inhibitors, such as cycloheximide and actinomycin D, sometime after their exposure to the double-stranded RNA (7).…”