Inverted factor access and slow reversion characterize SWI/SNF-altered nucleosome dimers
Inverted factor access and slow reversion characterize SWI/SNF-altered nucleosome dimers
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DOI：
10.1074/jbc.m609473200
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发表时间：
2007-01-12
影响因子：
4.8
通讯作者：
Schnitzler, Gavin R.
中科院分区：
文献类型：
--
作者：
Ulyanova, Natalia P.;Schnitzler, Gavin R.
人SWI/SNF（hSWI/SNF）是一种ATP依赖的染色质重塑复合物，在细胞基因的激活和抑制中具有重要功能。以前，我们表明，hSWI/SNF创建结构改变的二聚体从单核细胞的核心。最近，我们发现hSWI/SNF还在多核小体模板上产生丰富的结构改变的双核小体，称为altosomes。在这里，我们发现，二聚体恢复正常的核小体在一个类似的速率为altosomes，也可以被切割产生核小体颗粒与类似的迁移率单核小体。使用这些和其他共享的属性，我们提出了一个单一的模型，这两种类型的hSWI/SNF产品。此外，我们进一步表征了改变的二聚体对转录因子的可及性，并发现二聚体中的DNA在中间最容易接近，在末端最不容易接近，与正常单核细胞体的概况直接相反。我们还发现，转录因子的结合可以影响正常的核小体和二聚体作为hSWI/SNF产品的比例。hSWI/SNF产品和转录因子之间的相互作用的影响进行了讨论。
Human SWI/SNF (hSWI/SNF) is an ATP-dependent chromatin remodeling complex with important functions in activation and repression of cellular genes. Previously, we showed that hSWI/SNF creates structurally altered dimers from mononucleosome cores. More recently we found that hSWI/SNF also generates abundant structurally altered dinucleosomes, called altosomes, on polynucleosomal templates. Here, we find that dimers revert to normal nucleosomes at a similar rate as altosomes and can also be cleaved to yield nucleosomal particles with mobilities similar to mononucleosomes. Using these and other shared properties we propose a single model for both types of hSWI/SNF product. In addition, we further characterize the accessibility of altered dimers to transcription factors, and find that the DNA in dimers is most accessible in the middle and least accessible at the ends, directly opposite the profile of normal mononucleosomes. We also find that transcription factor binding can influence the ratio of normal nucleosomes and dimers as hSWI/SNF products. Implications for the interplay between hSWI/SNF products and transcription factors are discussed.