title: Upon the observation of superbeads in chromatin.
abstract: There exist some indications that nucleases recognize "superbeads" in chromatin. We show that a chromatin extract of rat liver which contains so-called "superbead"-peaks can be separated in a Mg++ soluble and a Mg++ insoluble fraction. The Mg++ insoluble fraction contains the full complement of histones and the expected DNA fragments, but has lost the characteristic peaks in sucrosegradient profiles. These discrete peaks are found in the Mg2+ soluble fraction of the chromatin extract. We give evidence that these peaks are RNP particles on the basis of their protein- and nucleic acid contents.
mesh_terms: D000818:Animals; D002499:Centrifugation, Density Gradient; D002843:Chromatin / Q000302:isolation & purification / Q000378:metabolism* / Q000648:ultrastructure; D008274:Magnesium; D009707:Nucleosomes / Q000378:metabolism; D051381:Rats; D012261:Ribonucleoproteins / Q000378:metabolism; D012995:Solubility
chemical_list: D002843:Chromatin; D009707:Nucleosomes; D012261:Ribonucleoproteins; D008274:Magnesium