Pashev I G, Nencheva M M, Markov G G
Biochim Biophys Acta. 1980 Apr 30;607(2):269-76. doi: 10.1016/0005-2787(80)90079-9.
Native and reconstituted chromatin from Ehrlich ascites tumor cells were fractionated into template-active and inactive fractions by the DNAase II/Mg2+-solubility method of Gottesfeld et al. (Gottesfeld, J.M., Garrard, W.T., Bagi, G., Wilson, R.F. and Bonner, J. (1974) Proc. Natl. Acad. Sci. U.S.A. 71, 2193-2197). The Mg2+-soluble (template-active) fractions were compared in respect to sedimentation behavior in sucrose gradients and the relative content of specific transcribed (ribosomal) and non-transcribed (satellite) DNA sequences. It was found that the Mg2+-soluble fraction of the native chromatin was enriched in ribosomal DNA while almost completely devoid of satellite DNA; the nucleoprotein monomer of this fraction sedimented in sucrose gradient at 14 S. Similar-results were obtained if chromatin was fractionated in the presence of 3 M urea. With reconstituted chromatin, however, neither the sedimentation profile, nor the relative content of ribosomal and satellite DNA sequences were recovered, thus indicating that reconstitution did not yield nucleoprotein structurally similar to native chromatin.
采用戈特斯费尔德等人（戈特斯费尔德，J.M.，加拉德，W.T.，巴吉，G.，威尔逊，R.F.和邦纳，J.（1974年）《美国国家科学院院刊》71，2193 - 2197）的DNA酶II/Mg²⁺溶解度法，将艾氏腹水瘤细胞的天然染色质和重组染色质分离为模板活性部分和非活性部分。比较了Mg²⁺可溶（模板活性）部分在蔗糖梯度中的沉降行为以及特定转录（核糖体）和非转录（卫星）DNA序列的相对含量。结果发现，天然染色质的Mg²⁺可溶部分富含核糖体DNA，而几乎完全不含卫星DNA；该部分的核蛋白单体在蔗糖梯度中沉降于14S处。如果在3M尿素存在下对染色质进行分级分离，也会得到类似结果。然而，对于重组染色质，无论是沉降图谱，还是核糖体和卫星DNA序列的相对含量都无法恢复，这表明重组并未产生结构上与天然染色质相似的核蛋白。
