title: A destabilized DNA conformation associated with tightly bound nuclear proteins in active genes of rat myoblast.
abstract: Purified nuclei from tissue cultured myoblasts were disrupted and centrifuged to equilibrium in a sarcosyl-caesium chloride gradient. A small portion (1.3% - 1.9%) of the non histone proteins (NHP) were banded with DNA in a high density region of the gradient. The DNA tightly bound to proteins representing about 0.6% of the total nuclear DNA was degraded after treating cell nuclei with S1 nuclease or DNAse I but resisted to mild micrococcal nuclease digestion. A large portion of the DNA sequences complementary to homologous RNA was concentrated in this DNA-proteins fraction. These finding suggest that a subset of NHP strongly associated to the active DNA regions play a role in the destabilisation of the double helical DNA during transcriptional processes.
mesh_terms: D000818:Animals; D001483:Base Sequence; D002868:Chromosomal Proteins, Non-Histone / Q000032:analysis; D004247:DNA / Q000032:analysis*; D003850:Deoxyribonuclease I; D004706:Endodeoxyribonucleases / Q000378:metabolism; D004720:Endonucleases / Q000378:metabolism; D008836:Micrococcal Nuclease / Q000378:metabolism; D009132:Muscles / Q000166:cytology*; D009690:Nucleic Acid Conformation; D009698:Nucleoproteins / Q000378:metabolism*; D051381:Rats; D015719:Single-Strand Specific DNA and RNA Endonucleases
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D009698:Nucleoproteins; D004247:DNA; D004706:Endodeoxyribonucleases; D004720:Endonucleases; D003850:Deoxyribonuclease I; D015719:Single-Strand Specific DNA and RNA Endonucleases; D008836:Micrococcal Nuclease