title: DNA supercoiling by core histone fractions and protamine.
abstract: The nuclear extract isolated from late Drosophila melanogaster embryos has Mg2+-dependent DNA topoisomerase 1 and nuclease activities. The extract facilitates the closed circular duplex DNA supercoiling in the presence of calf histone fractions H2A, H2B, H3 and H4, and fish protamine but not HI histone.
mesh_terms: D000818:Animals; D004264:DNA Topoisomerases, Type I / Q000378:metabolism; D004278:DNA, Superhelical; D004331:Drosophila melanogaster; D006657:Histones; D046911:Macromolecular Substances; D011479:Protamines
chemical_list: D004278:DNA, Superhelical; D006657:Histones; D046911:Macromolecular Substances; D011479:Protamines; D004264:DNA Topoisomerases, Type I