Lishanskaya A I, Mosevitsky M I
Nucleic Acids Res. 1976 Aug;3(8):2041-54. doi: 10.1093/nar/3.8.2041.
The minor chromatin fraction was isolated from the sonicated calf thymus nuclei on the basis of its differential solubility in the "quasiphysiological" salt medium (0.1 M KCl-0.05 M NaCl-l mM MgCl2-1 mM CaCl2). Histone Hl is almost completely absent from this fraction. DNA isolated from this fraction occurs in three discrete low mol. wt. fragments. The fraction of chromatin which lacks histone Hl can also be obtained by two other methods. On of them consists in salt precipitation of the chromatin gel and its subsequent sonication. The second method includes precipitation of the sonicated chromatin gel by salts. In the first case the properties of the chromatin fraction which remains in the supernatant after centrifugation closely resemble those of the original salt-soluble nuclear fraction. The second method yields supernatant fraction also lacking histone Hl but containing heterogeneous DNA. Comparisons were also made of the sonically-solubilized nuclear fractions obtained in the complete salt medium and its mono and divalent cationic constituents.
基于其在“准生理”盐介质（0.1M KCl - 0.05M NaCl - 1mM MgCl₂ - 1mM CaCl₂）中的不同溶解度，从小牛胸腺细胞核超声破碎物中分离出微量染色质部分。该部分几乎完全不含组蛋白H1。从该部分分离出的DNA以三个离散的低分子量片段形式存在。缺乏组蛋白H1的染色质部分也可通过其他两种方法获得。其中一种方法是对染色质凝胶进行盐沉淀并随后超声处理。第二种方法包括用盐沉淀超声破碎的染色质凝胶。在第一种情况下，离心后留在上清液中的染色质部分的性质与原始盐溶性核部分的性质非常相似。第二种方法得到的上清液部分也缺乏组蛋白H1，但含有异质DNA。还对在完全盐介质及其单价和二价阳离子成分中获得的超声溶解的核部分进行了比较。
