title: Characterization of nuclear structures containing superhelical DNA.
abstract: Structures resembling nuclei but depleted of protein may be released by gently lysing cells in solutions containing non-ionic detergents and high concentrations of salt. These nucleoids sediment in gradients containing intercalating agents in a manner characteristic of DNA that is intact, supercoiled and circular. The concentration of salt present during isolation of human nucleoids affects their protein content. When made in I-95 M NaCl they lack histones and most of the proteins characteristic of chromatin; in 1-0 M NaCl they contain variable amounts of histones. The effects of various treatments on nucleoid integrity were investigated.
mesh_terms: D000166:Acridines; D002458:Cell Fractionation; D002467:Cell Nucleus / Q000032:analysis / Q000187:drug effects / Q000528:radiation effects; D002478:Cells, Cultured; D002499:Centrifugation, Density Gradient; D004247:DNA; D005720:Gamma Rays; D006367:HeLa Cells; D008856:Microscopy, Fluorescence; D009690:Nucleic Acid Conformation; D009698:Nucleoproteins / Q000032:analysis; D011402:Pronase / Q000494:pharmacology; D012313:RNA / Q000032:analysis; D012260:Ribonucleases / Q000494:pharmacology; D012965:Sodium Chloride / Q000494:pharmacology; D013045:Species Specificity; D013696:Temperature
chemical_list: D000166:Acridines; D009698:Nucleoproteins; D012965:Sodium Chloride; D012313:RNA; D004247:DNA; D012260:Ribonucleases; D011402:Pronase