[电泳过程中相关寡核小体的形成机制]

[Mechanism of formation of associated oligonucleosomes during electrophoresis].

作者信息

Spirin K S, Grigor'ev S A, Krasheninnikov I A

出版信息

Mol Biol (Mosk). 1988 Nov-Dec;22(6):1530-8.

Abstract

Here we used DNP electrophoresis to study the mechanism of formation of associated oligonucleosomes (A-particles) which have been previously shown by Weintraub to contain the DNA of silent but not of transcriptionally-active genes from chicken erythrocyte nuclei. We found out that A-particles are generated in the course of electrophoresis and that their assembly is inhibited as the result of redistribution of the most mobile fraction of histones H1 and H5. The mechanism and the conditions for the assembly of A-particles at the start line of DNP electrophoresis are discussed in the paper. The DNA molecules constituting A-particles appeared to be about 60 base pairs longer than the DNA of free oligonucleosomes. Thus in course of nuclease treatment of erythrocyte nuclei two chromatin fractions can be observed, one of them containing the DNA of transcriptionally active genes loses its terminal DNA regions owing to rapid degradation of cleaved nucleosome linkers, while the other containing the DNA of repressed genes maintains its terminal linker DNA and gives rise to the associated oligonucleosomes.

摘要

在此，我们利用DNP电泳来研究相关寡核小体（A颗粒）的形成机制，此前温特劳布已证明，这些A颗粒含有来自鸡红细胞核中沉默基因而非转录活性基因的DNA。我们发现，A颗粒是在电泳过程中产生的，并且由于组蛋白H1和H5最易移动部分的重新分布，其组装受到抑制。本文讨论了在DNP电泳起始线处A颗粒组装的机制和条件。构成A颗粒的DNA分子似乎比游离寡核小体的DNA长约60个碱基对。因此，在对红细胞核进行核酸酶处理的过程中，可以观察到两种染色质组分，其中一种含有转录活性基因的DNA，由于裂解的核小体连接体的快速降解而失去其末端DNA区域，而另一种含有被抑制基因的DNA则保留其末端连接体DNA并产生相关的寡核小体。