Weintraub H
Cell. 1984 Aug;38(1):17-27. doi: 10.1016/0092-8674(84)90522-1.
I have identified a chromatin particle containing DNA as large as 20-40 kb that migrates as a discrete entity on agarose gels. With increasing nuclease digestion, the particle becomes cleaved in the linker regions between nucleosomes, but remains intact, probably held together by the outer histones, H1 and H5. By hybridization analysis, inactive genes are found in these particles. Active genes (and their flanking sequences) are also found in particles containing H1 and H5, but in contrast to inactive supranucleosome particles, active polynucleosome particles are not held together after cleavage of linker DNA. This suggests that H1 cross-links adjacent nucleosomes in inactive regions and that H1 is bound differently in expressed regions. The results raise the possibility that the marked degree of suppression of repressed, tissue-specific genes may be determined, in part, by their assembly into these inactive supranucleosome structures.
我已经鉴定出一种染色质颗粒，其包含大小达20 - 40 kb的DNA，在琼脂糖凝胶上作为一个离散实体迁移。随着核酸酶消化的增加，该颗粒在核小体之间的连接区被切割，但仍保持完整，可能是由外部组蛋白H1和H5维系在一起。通过杂交分析，在这些颗粒中发现了无活性基因。在含有H1和H5的颗粒中也发现了活性基因（及其侧翼序列），但与无活性的超核小体颗粒不同，连接DNA切割后，活性多核小体颗粒不会维系在一起。这表明H1在无活性区域交联相邻核小体，并且H1在表达区域的结合方式不同。这些结果增加了一种可能性，即被抑制的组织特异性基因的显著抑制程度可能部分取决于它们组装成这些无活性的超核小体结构。
