Verschure Pernette J, van der Kraan Ineke, Manders Erik M M, Hoogstraten Deborah, Houtsmuller Adriaan B, van Driel Roel
Swammerdam Institute for Life Sciences, BioCentrum Amsterdam, University of Amsterdam, Kruislaan 318, 1098 SM Amsterdam, The Netherlands.
EMBO Rep. 2003 Sep;4(9):861-6. doi: 10.1038/sj.embor.embor922. Epub 2003 Aug 22.
Most chromatin in interphase nuclei is part of condensed chromatin domains. Previous work has indicated that transcription takes place primarily at the surface of chromatin domains, that is, in the perichromatin region. It is possible that genes inside chromatin domains are silenced due to inaccessibility to macromolecular components of the transcription machinery. We have tested the accessibility of chromatin domains in nuclei of living cells with proteins and dextrans of different molecular sizes. Our results show that chromatin domains are readily accessible to large macromolecules, including proteins with a molecular weight of several hundred kilodaltons. Therefore, the silencing of genes that are incorporated into such domains is not due to the physical inaccessibility of condensed chromatin domains to transcription factors.
大多数处于间期细胞核中的染色质是浓缩染色质结构域的一部分。先前的研究表明，转录主要发生在染色质结构域的表面，即染色质周缘区域。染色质结构域内部的基因可能由于转录机制的大分子成分无法接近而被沉默。我们用不同分子大小的蛋白质和葡聚糖测试了活细胞核中染色质结构域的可及性。我们的结果表明，染色质结构域很容易被大分子接近，包括分子量达数百千道尔顿的蛋白质。因此，整合到这些结构域中的基因的沉默并非由于浓缩染色质结构域对转录因子在物理上不可及。
