Stalder J, Seebeck T, Braun R
Eur J Biochem. 1978 Oct;90(2):391-5. doi: 10.1111/j.1432-1033.1978.tb12616.x.
Treatment of nuclei from Physarum polycephalum with DNAse I leads to DNA fragments with a regular pattern of multiples of 10 nucleotides, when analyzed on gels under denaturing conditions as has been shown for other eukaryotes. Reports from Weintraub and Axel lead to the conclusion, that active genes are preferentially digested by DNAse I. When Physarum chromatin is degraded by DNAse I, the ribosomal genes are no longer available for hybridization with 19-S and 26-S rRNA and are thus preferentially destroyed. Degradation of chromatin from nuclei in mitosis, where no rRNA is synthesized and from nuclei in late G2 phase, where rRNA synthesis is maximal, leads to the same proportion of the ribosomal sequences being lost for hybridization. Therefore the preferential degradation of the ribosomal genes in Physarum by DNAse I probably does not reflect the actual momentary activity of these genes. This suggests that DNAse I treatment may distinguish between active chromatin and very strongly repressed chromatin.
用脱氧核糖核酸酶I处理多头绒泡菌的细胞核，在变性条件下于凝胶上进行分析时，会产生具有规则模式的、以10个核苷酸为倍数的DNA片段，这与其他真核生物的情况相同。温特劳布和阿克塞尔的报告得出结论，即活性基因优先被脱氧核糖核酸酶I消化。当多头绒泡菌染色质被脱氧核糖核酸酶I降解时，核糖体基因不再可用于与19 - S和26 - S rRNA杂交，因此被优先破坏。对有丝分裂期细胞核（此时不合成rRNA）和G2期后期细胞核（此时rRNA合成最大）的染色质进行降解，导致用于杂交的核糖体序列损失比例相同。因此，脱氧核糖核酸酶I对多头绒泡菌核糖体基因的优先降解可能并不反映这些基因的实际瞬时活性。这表明脱氧核糖核酸酶I处理可能能够区分活性染色质和受到极强抑制的染色质。
