Palstra Robert-Jan, Simonis Marieke, Klous Petra, Brasset Emilie, Eijkelkamp Bart, de Laat Wouter
Department of Cell Biology and Genetics, Erasmus MC, Rotterdam, The Netherlands.
PLoS One. 2008 Feb 20;3(2):e1661. doi: 10.1371/journal.pone.0001661.
A relationship exists between nuclear architecture and gene activity and it has been proposed that the activity of ongoing RNA polymerase II transcription determines genome organization in the mammalian cell nucleus. Recently developed 3C and 4C technology allowed us to test the importance of transcription for nuclear architecture. We demonstrate that upon transcription inhibition binding of RNA polymerase II to gene regulatory elements is severely reduced. However, contacts between regulatory DNA elements and genes in the beta-globin locus are unaffected and the locus still interacts with the same genomic regions elsewhere on the chromosome. This is a general phenomenon since the great majority of intra- and interchromosomal interactions with the ubiquitously expressed Rad23a gene are also not affected. Our data demonstrate that without transcription the organization and modification of nucleosomes at active loci and the local binding of specific trans-acting factors is unaltered. We propose that these parameters, more than transcription or RNA polymerase II binding, determine the maintenance of long-range DNA interactions.
核结构与基因活性之间存在关联，有人提出正在进行的RNA聚合酶II转录活性决定了哺乳动物细胞核中的基因组组织。最近开发的3C和4C技术使我们能够测试转录对核结构的重要性。我们证明，转录抑制后，RNA聚合酶II与基因调控元件的结合会严重减少。然而，β-珠蛋白基因座中调控DNA元件与基因之间的接触不受影响，该基因座仍与染色体上其他位置的相同基因组区域相互作用。这是一种普遍现象，因为与普遍表达的Rad23a基因的绝大多数染色体内和染色体间相互作用也不受影响。我们的数据表明，没有转录时，活性位点处核小体的组织和修饰以及特定反式作用因子的局部结合不会改变。我们提出，这些参数比转录或RNA聚合酶II结合更能决定远距离DNA相互作用的维持。
