Volume 9 Number 21981 Nucleic Acids Research Renaturation of DNA: a novel reaction of histones

Histones isolated from several sources, either singly or in combi-nation promote the renaturation of complementary single strands of DNA, as measured by the acquisition of resistance to S1 nuclease. The reaction is rapid (T <1 min), and i+stoic ometric pther than catalytic. Renatura-tip is stimulated by Mg, Mn, and Ca, but is strongly inhibited by Zn. Crude extracts of early embryos of Drosophila melanogaster possess renaturation activity which is protease sensitive, heat-stable, and acid-soluble, suggesting that most or all of it can be attributed to histones. This observation thus provides a functional assay for histones that should prove useful in studies of chromatin and histone-DNA interactions, as well as for the identification and isolation of histones and histone-like pro-teins in crude extracts