A partial characterization of DNA fragments protected from nuclease degradation in histone depleted metaphase chromosomes of the Chinese hamster.
A small proportion (0.1-0.5%) of the total DNA content of native Chinese hamster metaphase chromosomes is protected from nucleolytic degradation following the removal of histones by extraction with either 0.2 N HCl or 2 M NaCl, and remains attached to the nonhistone protein core. Acid extraction followed by DNase I digestion leads to small fragments of 10-30 bases. Salt extraction followed by micrococcal nuclease digestion gives approx. 140 b.p. fragments which are undistinguishable in size from nucleosome core DNA fragments. Furthermore, DNase I treatment of salt extracted chromosomes gives DNA fragments containing single strands which are multiples of 10 bases in length, again characteristic of the nucleosome structure. Reassociation kinetics using the 32P-labelled 140 b.p. fragments as probes suggests they are enriched for rapidly reassociating sequences.
D000818:Animals; D001483:Base Sequence; D002453:Cell Cycle; D002460:Cell Line; D002875:Chromosomes / Q000032:analysis*; D006224:Cricetinae; D004247:DNA / Q000032:analysis*; D004262:DNA Restriction Enzymes; D003851:Deoxyribonucleases; D006657:Histones / Q000302:isolation & purification*; D007700:Kinetics; D008168:Lung; D008677:Metaphase; D009695:Nucleic Acid Renaturation; D011116:Polynucleotide 5'-Hydroxyl-Kinase
D006657:Histones; D004247:DNA; D011116:Polynucleotide 5'-Hydroxyl-Kinase; D003851:Deoxyribonucleases; D004262:DNA Restriction Enzymes