[Discrete classes of linker DNA in chromatin].
Electron microscopic measurements of linker DNA were performed on chromatin from rat thymus cells and chicken erythrocytes which differ in biochemically determined DNA repeat sizes. The data obtained demonstrate that linker DNA is very heterogeneous in length and has size up to 100 nucleotide, pairs. Several discrete classes of linker DNA were revealed, they are multiples of 23--24 nucleotide pairs. The discrete and regular pattern of linker DNA classes allows to suggest that histone octamers have at least four zones of strong histone-histone interaction indispensable for tight contacts between nucleosomes. Provided the identity of packing of linker and core DNA, each turn of DNA should consist of about 95--100 nucleotide pairs. It gives a complete twist of nucleosomes along the axis of the chromatin thread through four zones of strong histone-histone interaction.
D000818:Animals; D002384:Catalysis; D002645:Chickens / Q000235:genetics; D002843:Chromatin / Q000032:analysis*; D004247:DNA / Q000032:analysis*; D004912:Erythrocytes / Q000032:analysis*; D008854:Microscopy, Electron; D012091:Repetitive Sequences, Nucleic Acid; D013950:Thymus Gland / Q000032:analysis*; D014357:Trypsin
D002843:Chromatin; D004247:DNA; D014357:Trypsin
Diskretnye klassy linkernoĭ DNK v khromatine.