Perturbation of nucleosome structure by the erythroid transcription factor GATA-1
Perturbation of nucleosome structure by the erythroid transcription factor GATA-1
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DOI：
10.1006/jmbi.1998.1783
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发表时间：
1998-06-12
影响因子：
5.6
通讯作者：
Felsenfeld, G
中科院分区：
文献类型：
--
作者：
Boyes, J;Omichinski, J;Felsenfeld, G
转录因子进入其染色质位点的能力需要破坏或置换覆盖启动子的核小体，这通过产生核酸酶超敏感位点来表示。我们在此证实了红细胞系因子加塔-1与携带加塔-1位点的核小体结合所引起的核小体结构的改变。DNase I和微球菌核酸酶探针显示，加塔-1结合导致组蛋白/DNA接触的广泛的、协同的断裂，以产生非常类似于由该因子与游离DNA形成的复合物。唯一不同的区域局限于核小体二分体轴周围的约50 bp，这似乎是DNA和组蛋白八聚体之间残留接触的区域。尽管组蛋白/DNA接触相当大的破坏，复合物在溶液中是完全稳定的，并且核小体的破坏是完全可逆的：它在去除转录因子后定量再生。此外，八聚体的组蛋白2A/2B组分不与外部竞争物交换。我们认为，这种复合物的形成可能是一个步骤，在一个完全超敏的网站在体内超过含有加塔家族结合位点的调控元件的产生。(C)出版社：Academic Press Limited。
The ability of transcription factors to gain access to their sites in chromatin requires the disruption or displacement of nucleosomes covering the promoter, signalled by the generation of a nuclease hypersensitive site. We characterise here the alterations in nucleosome structure caused by binding of the erythroid factor GATA-1 to a nucleosome carrying GATA-1 sites. DNase I and micrococcal nuclease probes show that GATA-1 binding causes extensive, cooperative breakage of the histone/DNA contacts to generate a complex very similar to that formed by the factor with free DNA. The only region which differs is confined to about 50 bp surrounding the nucleosome dyad axis which appears to be the domain of residual contact between the DNA and histone octamer. Despite considerable breakage of the histone/DNA contacts, the complex is completely stable in solution, and disruption of the nucleosome is entirely reversible: it is regenerated quantitatively upon removal of the transcription factor. Moreover, the histone 2A/2B component of the octamer does not exchange to external competitor. We suggest that formation of this complex may be a step in the generation of a fully hypersensitive site in viva over regulatory elements containing GATA family binding sites. (C) 1998 Academic Press Limited.